SELECT 
  variant_id, 
  yml2_unit 
FROM 
  cscart_product_feature_variant_descriptions 
WHERE 
  variant_id IN (
    '577', '591', '1476', '1806', '1', '1298', 
    '1818', '1809', '1299', '1297', '1471', 
    '273', '164', '1814', '1817', '122', 
    '121', '127', '149', '120', '123', 
    '152', '146', '50', '57', '58', '1472', 
    '147', '176', '30', '29', '298', '423', 
    '1303', '1300', '1810', '237', '238', 
    '98', '1475', '376', '165'
  ) 
  AND lang_code = 'kk'

Query time 0.00063

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "29.41"
    },
    "table": {
      "table_name": "cscart_product_feature_variant_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "variant_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 42,
      "rows_produced_per_join": 42,
      "filtered": "100.00",
      "index_condition": "((`test_uchur_k`.`cscart_product_feature_variant_descriptions`.`variant_id` in ('577','591','1476','1806','1','1298','1818','1809','1299','1297','1471','273','164','1814','1817','122','121','127','149','120','123','152','146','50','57','58','1472','147','176','30','29','298','423','1303','1300','1810','237','238','98','1475','376','165')) and (`test_uchur_k`.`cscart_product_feature_variant_descriptions`.`lang_code` = 'kk'))",
      "cost_info": {
        "read_cost": "25.21",
        "eval_cost": "4.20",
        "prefix_cost": "29.41",
        "data_read_per_join": "130K"
      },
      "used_columns": [
        "variant_id",
        "lang_code",
        "yml2_unit"
      ]
    }
  }
}