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 (
    33363, 4281, 38101, 33709, 41401, 5792, 
    35912, 40532, 1998, 45021, 764, 2454, 
    288, 40527, 49199, 44933, 5236, 37413, 
    41383, 36765, 36270, 4288, 32690, 27290, 
    37420, 6439, 6403, 33360, 44560, 3614, 
    4287, 3979
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.02284

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_descriptions",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "PRIMARY",
          "key_length": "11",
          "used_key_parts": ["product_id", "lang_code"],
          "rows": 32,
          "filtered": 100,
          "index_condition": "cscart_product_descriptions.product_id in (33363,4281,38101,33709,41401,5792,35912,40532,1998,45021,764,2454,288,40527,49199,44933,5236,37413,41383,36765,36270,4288,32690,27290,37420,6439,6403,33360,44560,3614,4287,3979) and cscart_product_descriptions.lang_code = 'en'"
        }
      }
    ]
  }
}