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, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    433161, 424229, 448141, 452096, 439269, 
    435935, 439815, 450361, 439963, 402412, 
    402497, 410461, 454777, 427310, 441321, 
    444113, 417555, 454342, 445485, 408738, 
    428075, 410195, 428819, 404494, 454049, 
    440255, 459252, 405167, 401806, 425534, 
    438532, 458860
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00598

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.0564324,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_descriptions",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["product_id", "lang_code"],
          "loops": 1,
          "rows": 32,
          "cost": 0.0564324,
          "filtered": 100,
          "attached_condition": "cscart_product_descriptions.product_id in (433161,424229,448141,452096,439269,435935,439815,450361,439963,402412,402497,410461,454777,427310,441321,444113,417555,454342,445485,408738,428075,410195,428819,404494,454049,440255,459252,405167,401806,425534,438532,458860) and cscart_product_descriptions.lang_code = 'en'"
        }
      }
    ]
  }
}