SELECT 
  cscart_product_feature_variant_descriptions.variant, 
  cscart_product_feature_variants.variant_id, 
  cscart_product_feature_variants.feature_id, 
  cscart_product_features_values.variant_id as selected, 
  cscart_product_features.feature_type, 
  cscart_seo_names.name as seo_name, 
  cscart_seo_names.path as seo_path, 
  cscart_product_feature_variants.mdc_variant 
FROM 
  cscart_product_feature_variants 
  LEFT JOIN cscart_product_feature_variant_descriptions ON cscart_product_feature_variant_descriptions.variant_id = cscart_product_feature_variants.variant_id 
  AND cscart_product_feature_variant_descriptions.lang_code = 'en' 
  INNER JOIN cscart_product_features_values ON cscart_product_features_values.variant_id = cscart_product_feature_variants.variant_id 
  AND cscart_product_features_values.lang_code = 'en' 
  AND cscart_product_features_values.product_id = 349 
  AND cscart_product_features_values.feature_id = cscart_product_feature_variants.feature_id 
  LEFT JOIN cscart_product_features ON cscart_product_features.feature_id = cscart_product_feature_variants.feature_id 
  LEFT JOIN cscart_seo_names ON cscart_seo_names.object_id = cscart_product_feature_variants.variant_id 
  AND cscart_seo_names.type = 'e' 
  AND cscart_seo_names.dispatch = '' 
  AND cscart_seo_names.lang_code = 'en' 
WHERE 
  1 
  AND cscart_product_feature_variants.feature_id IN (
    1055, 1107, 1041, 1057, 1046, 1050, 1072, 
    1059, 1047, 1073, 1113, 1067, 1061, 
    1064, 1044, 1069, 1114, 1056, 1052, 
    1063, 1070, 1054, 1108, 1062, 1043, 
    1053, 1060, 1068, 1045, 1115
  ) 
GROUP BY 
  cscart_product_feature_variants.variant_id 
ORDER BY 
  cscart_product_feature_variants.position, 
  cscart_product_feature_variant_descriptions.variant

Query time 0.00233

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "22.88"
    },
    "ordering_operation": {
      "using_filesort": true,
      "grouping_operation": {
        "using_temporary_table": true,
        "using_filesort": false,
        "nested_loop": [
          {
            "table": {
              "table_name": "cscart_product_features_values",
              "access_type": "ref",
              "possible_keys": [
                "PRIMARY",
                "fl",
                "variant_id",
                "lang_code",
                "product_id",
                "fpl",
                "idx_product_feature_variant_id"
              ],
              "key": "idx_product_feature_variant_id",
              "used_key_parts": [
                "product_id"
              ],
              "key_length": "3",
              "ref": [
                "const"
              ],
              "rows_examined_per_scan": 11,
              "rows_produced_per_join": 4,
              "filtered": "41.13",
              "using_index": true,
              "cost_info": {
                "read_cost": "1.40",
                "eval_cost": "0.90",
                "prefix_cost": "3.60",
                "data_read_per_join": "3K"
              },
              "used_columns": [
                "feature_id",
                "product_id",
                "variant_id",
                "lang_code"
              ],
              "attached_condition": "((`danishecarter_25_march`.`cscart_product_features_values`.`feature_id` in (1055,1107,1041,1057,1046,1050,1072,1059,1047,1073,1113,1067,1061,1064,1044,1069,1114,1056,1052,1063,1070,1054,1108,1062,1043,1053,1060,1068,1045,1115)) and (`danishecarter_25_march`.`cscart_product_features_values`.`lang_code` = 'en'))"
            }
          },
          {
            "table": {
              "table_name": "cscart_product_feature_variants",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY",
                "feature_id"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "variant_id"
              ],
              "key_length": "3",
              "ref": [
                "danishecarter_25_march.cscart_product_features_values.variant_id"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 1,
              "filtered": "38.54",
              "cost_info": {
                "read_cost": "4.52",
                "eval_cost": "0.35",
                "prefix_cost": "9.03",
                "data_read_per_join": "4K"
              },
              "used_columns": [
                "variant_id",
                "feature_id",
                "position",
                "mdc_variant"
              ],
              "attached_condition": "(`danishecarter_25_march`.`cscart_product_feature_variants`.`feature_id` = `danishecarter_25_march`.`cscart_product_features_values`.`feature_id`)"
            }
          },
          {
            "table": {
              "table_name": "cscart_product_features",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "feature_id"
              ],
              "key_length": "3",
              "ref": [
                "danishecarter_25_march.cscart_product_features_values.feature_id"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 1,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "1.74",
                "eval_cost": "0.35",
                "prefix_cost": "11.13",
                "data_read_per_join": "2K"
              },
              "used_columns": [
                "feature_id",
                "feature_type"
              ]
            }
          },
          {
            "table": {
              "table_name": "cscart_product_feature_variant_descriptions",
              "access_type": "eq_ref",
              "possible_keys": [
                "PRIMARY"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "variant_id",
                "lang_code"
              ],
              "key_length": "9",
              "ref": [
                "danishecarter_25_march.cscart_product_features_values.variant_id",
                "const"
              ],
              "rows_examined_per_scan": 1,
              "rows_produced_per_join": 1,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "1.74",
                "eval_cost": "0.35",
                "prefix_cost": "13.22",
                "data_read_per_join": "5K"
              },
              "used_columns": [
                "variant_id",
                "variant",
                "lang_code"
              ]
            }
          },
          {
            "table": {
              "table_name": "cscart_seo_names",
              "access_type": "ref",
              "possible_keys": [
                "PRIMARY",
                "dispatch"
              ],
              "key": "PRIMARY",
              "used_key_parts": [
                "object_id",
                "type",
                "dispatch",
                "lang_code"
              ],
              "key_length": "206",
              "ref": [
                "danishecarter_25_march.cscart_product_features_values.variant_id",
                "const",
                "const",
                "const"
              ],
              "rows_examined_per_scan": 4,
              "rows_produced_per_join": 6,
              "filtered": "100.00",
              "cost_info": {
                "read_cost": "8.27",
                "eval_cost": "1.39",
                "prefix_cost": "22.88",
                "data_read_per_join": "11K"
              },
              "used_columns": [
                "name",
                "object_id",
                "type",
                "dispatch",
                "path",
                "lang_code"
              ]
            }
          }
        ]
      }
    }
  }
}

Result

variant variant_id feature_id selected feature_type seo_name seo_path mdc_variant
100 25427 1060 25427 N 100
10000 24069 1052 24069 N 10000
12000 25684 1108 25684 N 12000
1500 26006 1062 26006 N
15000 26052 1063 26052 N
2 (Red) 25432 1061 25432 S EMISSIONSSTICKER_RED
2015 26007 1046 26007 N
201510 26024 1064 26024 N 201510
3 Days 24086 1055 24086 S 3_days
50 25486 1073 25486 N 50
6 25416 1059 25416 N 6
8x4 25716 1115 25716 S WHEEL_DRIVE_8x4
ABARTH 24388 1056 24388 E abarth ABARTH
Adaptive Cruise Control 25485 1072 25485 S ADAPTIVE_CRUISE_CONTROL
Ads with pictures 24079 1054 24079 M ads_with_pictures
Automatic air conditioning 25400 1057 25400 S AUTOMATIC_CLIMATISATION
Cattle truck 24192 1041 24192 S CattleTruckSemiTrailer
Dealer 24073 1053 24073 S dealer
Euro 7 25460 1067 25460 S EURO7
Fixed 23789 1043 23789 S FIXED
Germany 23864 1050 23864 S DE
Local traffic 25705 1113 25705 S LOCAL_TRAFFIC
Manual gearbox 25465 1069 25465 S MANUAL_GEAR
More than 3 25678 1107 25678 S n
Natural Gas 23795 1044 23795 S CNG
No 23805 1047 23805 S N
Purple 25475 1070 25475 S PURPLE
Push Floor Hydraulic Installation 25708 1114 25708 S PUSH_FLOOR_HYDRAULIC_INSTALLATION
Service book maintained 24077 1054 24077 M service_book_maintained
Trailer coupling preparation 25461 1068 25461 S TRAILER_COUPLING_PREPARATION
Used vehicle 23802 1045 23802 S USED