SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    121, 119, 141, 23, 4, 142, 120, 62, 108, 
    107, 94, 8, 86, 54, 10, 93, 12, 32, 7, 130, 
    35, 16, 33, 110, 34, 89, 147, 114, 36, 
    128, 20, 52, 84, 109, 118, 19, 131, 146, 
    13, 61, 95, 15, 9, 85, 59, 111, 144, 60, 
    123, 145, 113, 6, 14, 63, 136, 50984, 
    127, 134, 42, 50985, 50986, 50988, 50993, 
    50992
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00104

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "44.81"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 64,
      "rows_produced_per_join": 64,
      "filtered": "100.00",
      "index_condition": "((`test_uchur_k`.`cscart_product_descriptions`.`product_id` in (121,119,141,23,4,142,120,62,108,107,94,8,86,54,10,93,12,32,7,130,35,16,33,110,34,89,147,114,36,128,20,52,84,109,118,19,131,146,13,61,95,15,9,85,59,111,144,60,123,145,113,6,14,63,136,50984,127,134,42,50985,50986,50988,50993,50992)) and (`test_uchur_k`.`cscart_product_descriptions`.`lang_code` = 'ru'))",
      "cost_info": {
        "read_cost": "38.41",
        "eval_cost": "6.40",
        "prefix_cost": "44.81",
        "data_read_per_join": "292K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text",
        "unit_name"
      ]
    }
  }
}