SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'en' 
WHERE 
  pfv.variant_id IN (
    1495, 1199, 1515, 1368, 1516, 1201, 1200, 
    1198, 1498, 8210, 37921, 37925, 1525, 
    1193, 1195, 1194, 59499, 1494, 59761, 
    1518, 38109, 1197, 1523, 1524, 7431, 
    1517, 7721, 1493, 38111, 1465, 37919
  )

Query time 0.00100

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "80.64"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "pfvd",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id",
            "lang_code"
          ],
          "key_length": "9",
          "rows_examined_per_scan": 31,
          "rows_produced_per_join": 31,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "37.24",
            "eval_cost": "6.20",
            "prefix_cost": "43.44",
            "data_read_per_join": "139K"
          },
          "used_columns": [
            "variant_id",
            "variant",
            "lang_code"
          ],
          "attached_condition": "((`webmarco`.`pfvd`.`variant_id` in (1495,1199,1515,1368,1516,1201,1200,1198,1498,8210,37921,37925,1525,1193,1195,1194,59499,1494,59761,1518,38109,1197,1523,1524,7431,1517,7721,1493,38111,1465,37919)) and (`webmarco`.`pfvd`.`lang_code` = 'en'))"
        }
      },
      {
        "table": {
          "table_name": "pfv",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "webmarco.pfvd.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 31,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "31.00",
            "eval_cost": "6.20",
            "prefix_cost": "80.64",
            "data_read_per_join": "35K"
          },
          "used_columns": [
            "variant_id",
            "position"
          ]
        }
      }
    ]
  }
}