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 (
    21557, 22623, 18937, 18940, 18943, 19239, 
    19245, 23006, 21545, 19227, 21605, 
    21607, 18900, 23005, 22582, 18848, 
    21563, 21564, 21722, 21549
  ) 
ORDER BY 
  cscart_product_feature_variants.position ASC, 
  cscart_product_feature_variant_descriptions.variant ASC

Query time 0.00347

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "72.01"
    },
    "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": 20,
            "rows_produced_per_join": 20,
            "filtered": "100.00",
            "index_condition": "(`danishecarter_latest`.`cscart_product_feature_variants`.`variant_id` in (21557,22623,18937,18940,18943,19239,19245,23006,21545,19227,21605,21607,18900,23005,22582,18848,21563,21564,21722,21549))",
            "cost_info": {
              "read_cost": "44.01",
              "eval_cost": "4.00",
              "prefix_cost": "48.01",
              "data_read_per_join": "52K"
            },
            "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_latest.cscart_product_feature_variants.variant_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 20,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "20.00",
              "eval_cost": "4.00",
              "prefix_cost": "72.01",
              "data_read_per_join": "60K"
            },
            "used_columns": [
              "variant_id",
              "variant",
              "lang_code"
            ]
          }
        }
      ]
    }
  }
}