SELECT 
  variant_id, 
  yml2_unit 
FROM 
  cscart_product_feature_variant_descriptions 
WHERE 
  variant_id IN (
    '1462', '1', '3', '158', '366', '300', 
    '289', '125', '126', '148', '367', 
    '281', '311', '1830', '1826', '1463', 
    '1465', '290', '160', '302', '155', 
    '122', '121', '127', '1349', '149', 
    '120', '123', '234', '146', '50', '57', 
    '58', '147', '9', '11', '10', '8', '7', 
    '43', '22', '26', '1453', '267', '287', 
    '294', '262', '162', '263', '110', 
    '1833', '265', '1305', '282', '111', 
    '1832', '1300', '54', '1466', '304', 
    '303', '237', '238', '98', '232', '170', 
    '154', '165'
  ) 
  AND lang_code = 'ru'

Query time 0.00151

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "47.61"
    },
    "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": 68,
      "rows_produced_per_join": 68,
      "filtered": "100.00",
      "index_condition": "((`test_uchur_k`.`cscart_product_feature_variant_descriptions`.`variant_id` in ('1462','1','3','158','366','300','289','125','126','148','367','281','311','1830','1826','1463','1465','290','160','302','155','122','121','127','1349','149','120','123','234','146','50','57','58','147','9','11','10','8','7','43','22','26','1453','267','287','294','262','162','263','110','1833','265','1305','282','111','1832','1300','54','1466','304','303','237','238','98','232','170','154','165')) and (`test_uchur_k`.`cscart_product_feature_variant_descriptions`.`lang_code` = 'ru'))",
      "cost_info": {
        "read_cost": "40.81",
        "eval_cost": "6.80",
        "prefix_cost": "47.61",
        "data_read_per_join": "211K"
      },
      "used_columns": [
        "variant_id",
        "lang_code",
        "yml2_unit"
      ]
    }
  }
}