SELECT 
  cscart_product_feature_variants.variant_id, 
  cscart_product_feature_variants.position, 
  cscart_product_feature_variants.color, 
  cscart_product_feature_variant_descriptions.variant 
FROM 
  cscart_product_feature_variants 
  LEFT JOIN cscart_product_feature_variant_descriptions ON cscart_product_feature_variants.variant_id = cscart_product_feature_variant_descriptions.variant_id 
  AND cscart_product_feature_variant_descriptions.lang_code = 'en' 
WHERE 
  cscart_product_feature_variants.variant_id IN (
    21570, 17539, 17542, 21587, 17538, 17617, 
    17741, 17753, 17759, 18672, 18644
  ) 
ORDER BY 
  cscart_product_feature_variants.position ASC, 
  cscart_product_feature_variant_descriptions.variant ASC

Query time 0.00157

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "39.61"
    },
    "ordering_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_product_feature_variants",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "variant_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 11,
            "rows_produced_per_join": 11,
            "filtered": "100.00",
            "index_condition": "(`danishecarter_25_march`.`cscart_product_feature_variants`.`variant_id` in (21570,17539,17542,21587,17538,17617,17741,17753,17759,18672,18644))",
            "cost_info": {
              "read_cost": "24.21",
              "eval_cost": "2.20",
              "prefix_cost": "26.41",
              "data_read_per_join": "29K"
            },
            "used_columns": [
              "variant_id",
              "color",
              "position"
            ]
          }
        },
        {
          "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_feature_variants.variant_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 11,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "11.00",
              "eval_cost": "2.20",
              "prefix_cost": "39.61",
              "data_read_per_join": "33K"
            },
            "used_columns": [
              "variant_id",
              "variant",
              "lang_code"
            ]
          }
        }
      ]
    }
  }
}