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 (
    94417, 94418, 94419, 94420, 94421, 94422, 
    94423, 94424, 94425, 94426, 94427, 
    94429, 94430, 94431, 94432, 94433, 
    94434, 94439, 94440, 94441, 94854, 
    94855, 94856, 94857
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.82"
    },
    "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": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.42",
        "eval_cost": "2.40",
        "prefix_cost": "10.82",
        "data_read_per_join": "91K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (94417,94418,94419,94420,94421,94422,94423,94424,94425,94426,94427,94429,94430,94431,94432,94433,94434,94439,94440,94441,94854,94855,94856,94857)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94417
94418
94419
94420
94421
94422
94423
94424
94425
94426
94427
94429
94430
94431
94432
94433
94434
94439
94440
94441
94854
94855
94856
94857