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 (
    1668, 1667, 1666, 3006, 3705, 6214, 6275, 
    6802, 6849, 6740, 6600, 6856, 6861, 
    6868, 6951, 6979, 7131, 7202, 7238, 
    7239, 7277, 7290, 7340, 7325, 7346, 
    8274, 8262, 8315, 8539, 8936, 9152, 
    9499, 8457, 6402, 9621, 3606, 8606, 
    8942, 2078, 9593, 7871, 7203, 9597, 
    9707, 9715, 8564
  ) 
ORDER BY 
  cscart_product_feature_variants.position ASC, 
  cscart_product_feature_variant_descriptions.variant ASC

Query time 0.00135

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "48.31"
    },
    "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": 46,
            "rows_produced_per_join": 46,
            "filtered": "100.00",
            "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_feature_variants`.`variant_id` in (1668,1667,1666,3006,3705,6214,6275,6802,6849,6740,6600,6856,6861,6868,6951,6979,7131,7202,7238,7239,7277,7290,7340,7325,7346,8274,8262,8315,8539,8936,9152,9499,8457,6402,9621,3606,8606,8942,2078,9593,7871,7203,9597,9707,9715,8564))",
            "cost_info": {
              "read_cost": "27.61",
              "eval_cost": "4.60",
              "prefix_cost": "32.21",
              "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": [
              "softwarepirmam_hewadelivard_cscart_4.cscart_product_feature_variants.variant_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 46,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "11.50",
              "eval_cost": "4.60",
              "prefix_cost": "48.31",
              "data_read_per_join": "139K"
            },
            "used_columns": [
              "variant_id",
              "variant",
              "lang_code"
            ]
          }
        }
      ]
    }
  }
}