SELECT 
  v.variant_id, 
  v.product_id, 
  vd.variant, 
  vf.position, 
  vf.color 
FROM 
  cscart_product_features_values v 
  LEFT JOIN cscart_product_feature_variant_descriptions vd ON v.variant_id = vd.variant_id 
  AND vd.lang_code = 'en' 
  LEFT JOIN cscart_product_feature_variants vf ON v.variant_id = vf.variant_id 
WHERE 
  1 
  AND v.feature_id = 1421 
  AND v.product_id IN (
    '60881', '60909', '60908', '60907', 
    '60906', '60905', '60904', '60903', 
    '60902', '60901', '60900', '60899', 
    '60898', '60897', '60896', '60910', 
    '60911', '60912', '60913', '60914', 
    '60915', '60916', '60917', '60918', 
    '60919', '60920', '60921', '60922', 
    '60923', '60924'
  )

Query time 0.00134

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "27.55"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "v",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id",
            "product_id"
          ],
          "key_length": "6",
          "rows_examined_per_scan": 30,
          "rows_produced_per_join": 30,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "3.55",
            "eval_cost": "3.00",
            "prefix_cost": "6.55",
            "data_read_per_join": "23K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id"
          ],
          "attached_condition": "((`cscartdb`.`v`.`feature_id` = 1421) and (`cscartdb`.`v`.`product_id` in ('60881','60909','60908','60907','60906','60905','60904','60903','60902','60901','60900','60899','60898','60897','60896','60910','60911','60912','60913','60914','60915','60916','60917','60918','60919','60920','60921','60922','60923','60924')))"
        }
      },
      {
        "table": {
          "table_name": "vd",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id",
            "lang_code"
          ],
          "key_length": "9",
          "ref": [
            "cscartdb.v.variant_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 30,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "7.50",
            "eval_cost": "3.00",
            "prefix_cost": "17.05",
            "data_read_per_join": "90K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ]
        }
      },
      {
        "table": {
          "table_name": "vf",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "cscartdb.v.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 30,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "7.50",
            "eval_cost": "3.00",
            "prefix_cost": "27.55",
            "data_read_per_join": "34K"
          },
          "used_columns": [
            "variant_id",
            "color",
            "position"
          ]
        }
      }
    ]
  }
}