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 (
    22172, 2873, 2854, 22268, 1942, 2857, 
    22214, 1945, 22263, 2859, 1946, 44946, 
    44943, 44944, 44947, 47974, 44945, 
    44281
  ) 
  AND cscart_product_descriptions.lang_code = 'vi'

Query time 0.00602

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": 18,
          "filtered": 100,
          "index_condition": "cscart_product_descriptions.product_id in (22172,2873,2854,22268,1942,2857,22214,1945,22263,2859,1946,44946,44943,44944,44947,47974,44945,44281) and cscart_product_descriptions.lang_code = 'vi'"
        }
      }
    ]
  }
}