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 (
    88167, 88215, 88192, 88204, 88400, 84769, 
    84782, 84791, 85663, 85683, 85695, 
    85707, 87448, 88492, 84764, 85659, 
    89019, 89104, 89112, 87504, 87520, 
    88444, 88462, 88478, 90831, 88191, 
    88203, 87536, 88399, 88493
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00043

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 (88167,88215,88192,88204,88400,84769,84782,84791,85663,85683,85695,85707,87448,88492,84764,85659,89019,89104,89112,87504,87520,88444,88462,88478,90831,88191,88203,87536,88399,88493)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}