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 (
    89686, 88383, 88384, 89683, 89684, 88363, 
    88109, 88121, 88133, 88280, 88281, 
    88282, 88357, 89680, 89681, 89682, 
    88362, 88108, 88120, 88132, 88276, 
    88277, 88278, 88279
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00067

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 (89686,88383,88384,89683,89684,88363,88109,88121,88133,88280,88281,88282,88357,89680,89681,89682,88362,88108,88120,88132,88276,88277,88278,88279)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}