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 (
    97582, 97583, 97584, 97585, 97586, 97874, 
    97875, 97876, 97877, 97878, 97879, 
    97880, 97881, 97882, 97883, 97884, 
    97885, 97886, 97887, 97888, 97889, 
    98001, 98176, 98177, 98178, 98179, 
    98180, 98181, 98182, 98183, 98184, 
    98185, 98186, 98187, 98188, 98189, 
    98190, 98191, 98200, 98201, 98202, 
    98203, 98204, 98205, 98206, 98207, 
    98391, 98392
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00099

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "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 (97582,97583,97584,97585,97586,97874,97875,97876,97877,97878,97879,97880,97881,97882,97883,97884,97885,97886,97887,97888,97889,98001,98176,98177,98178,98179,98180,98181,98182,98183,98184,98185,98186,98187,98188,98189,98190,98191,98200,98201,98202,98203,98204,98205,98206,98207,98391,98392)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}