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 (
    37300, 4795, 38150, 37296, 26849, 27056, 
    37294, 41358, 26856, 37302, 37284, 
    41368, 3464, 4865, 41387, 31645, 41367, 
    37942, 41134, 4793, 41102, 37289, 5761, 
    37943, 37301, 32319, 923, 610, 36303, 
    38148, 37297, 33696
  ) 
  AND cscart_product_descriptions.lang_code = 'vi'

Query time 0.00481

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 (37300,4795,38150,37296,26849,27056,37294,41358,26856,37302,37284,41368,3464,4865,41387,31645,41367,37942,41134,4793,41102,37289,5761,37943,37301,32319,923,610,36303,38148,37297,33696) and cscart_product_descriptions.lang_code = 'vi'"
        }
      }
    ]
  }
}