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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    87422, 88975, 88538, 88687, 88734, 89034, 
    88546, 87540, 87430, 89105, 85675, 
    88423, 88527, 88580, 87426, 87427, 
    88966, 84771, 84784, 84793, 89788, 
    88544, 84766, 88965, 88579, 88964, 
    88963, 87766, 87772, 87775, 87765, 
    87771, 87774, 88680, 88682, 88727, 
    88729, 88774, 88776, 88572, 88574, 
    88679, 88681, 88726, 88728, 88773, 
    88775, 88570
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00106

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (87422,88975,88538,88687,88734,89034,88546,87540,87430,89105,85675,88423,88527,88580,87426,87427,88966,84771,84784,84793,89788,88544,84766,88965,88579,88964,88963,87766,87772,87775,87765,87771,87774,88680,88682,88727,88729,88774,88776,88572,88574,88679,88681,88726,88728,88773,88775,88570)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}