SELECT 
  pfv.feature_id, 
  pfv.product_id, 
  pfv.variant_id, 
  fv.position, 
  fvd.variant 
FROM 
  cscart_product_features_values AS pfv 
  INNER JOIN cscart_product_feature_variants AS fv ON pfv.feature_id = fv.feature_id 
  AND pfv.variant_id = fv.variant_id 
  INNER JOIN cscart_product_feature_variant_descriptions AS fvd ON pfv.variant_id = fvd.variant_id 
  AND fvd.lang_code = 'en' 
WHERE 
  pfv.feature_id IN (549, 553, 548) 
  AND pfv.product_id IN (
    466, 467, 468, 469, 470, 471, 472, 473, 
    474, 475, 476, 477, 478, 479, 480, 481, 
    482, 483, 484, 485, 486, 487, 488, 489, 
    490, 491, 492, 493, 494, 495, 496, 497, 
    498, 499, 500, 501, 502, 503, 504, 505, 
    506, 507, 508, 509, 510, 511, 512, 513, 
    514, 515
  ) 
  AND pfv.lang_code = 'en'

Query time 0.00227

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "63.44"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "fvd",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY"
          ],
          "rows_examined_per_scan": 141,
          "rows_produced_per_join": 14,
          "filtered": "10.00",
          "cost_info": {
            "read_cost": "39.60",
            "eval_cost": "2.82",
            "prefix_cost": "42.42",
            "data_read_per_join": "42K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ],
          "attached_condition": "(`atulecarter_atul_demo2`.`fvd`.`lang_code` = 'en')"
        }
      },
      {
        "table": {
          "table_name": "fv",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "feature_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "atulecarter_atul_demo2.fvd.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "9.22",
          "cost_info": {
            "read_cost": "14.10",
            "eval_cost": "0.26",
            "prefix_cost": "59.34",
            "data_read_per_join": "1K"
          },
          "used_columns": [
            "variant_id",
            "feature_id",
            "position"
          ],
          "attached_condition": "(`atulecarter_atul_demo2`.`fv`.`feature_id` in (549,553,548))"
        }
      },
      {
        "table": {
          "table_name": "pfv",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "variant_id",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id"
          ],
          "key_length": "3",
          "ref": [
            "atulecarter_atul_demo2.fv.feature_id"
          ],
          "rows_examined_per_scan": 9,
          "rows_produced_per_join": 0,
          "filtered": "1.28",
          "using_index": true,
          "cost_info": {
            "read_cost": "1.76",
            "eval_cost": "0.03",
            "prefix_cost": "63.44",
            "data_read_per_join": "118"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "lang_code"
          ],
          "attached_condition": "((`atulecarter_atul_demo2`.`pfv`.`variant_id` = `atulecarter_atul_demo2`.`fvd`.`variant_id`) and (`atulecarter_atul_demo2`.`pfv`.`product_id` in (466,467,468,469,470,471,472,473,474,475,476,477,478,479,480,481,482,483,484,485,486,487,488,489,490,491,492,493,494,495,496,497,498,499,500,501,502,503,504,505,506,507,508,509,510,511,512,513,514,515)) and (`atulecarter_atul_demo2`.`pfv`.`lang_code` = 'en'))"
        }
      }
    ]
  }
}