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 (
    91061, 88063, 91063, 91062, 91057, 91060, 
    91055, 91058, 91056, 91059, 84848, 
    84912, 87976, 87967, 84910, 87982, 
    87977, 88089, 87968, 88039, 91064, 
    88016, 93151, 93152, 93153, 93155, 
    93157, 93796, 94810, 94825
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00080

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (91061,88063,91063,91062,91057,91060,91055,91058,91056,91059,84848,84912,87976,87967,84910,87982,87977,88089,87968,88039,91064,88016,93151,93152,93153,93155,93157,93796,94810,94825)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}