SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '', 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (4491, 4490, 4492) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "product_id",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 3,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (4491,4490,4492)",
      "attached_condition": "cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text
4490 <p>Convenient, lightweight carry holder for SL Series radios. Swivel belt clip allows you to adjust the radio for a comfortable fit on your belt. Compatible with SL 7000 and SL 7000e series.</p> SL7550 Case, SL7580 Case, SL7590 Cases, SL 7550e, SL 7580e, SL 7590e
4491 <p>This nylon strap wraps conveniently around the wrist to allow you to easily carry your SL Series radio and provides additional protection against accidental drops.</p> SL7550 Case, SL7580 Case, SL7590 Cases, TLK110 case, TLK110 strap, TLK110 wrist strap, TLK 110 case, TLK 110 strap, TLK 110 wrist strap
4492 SL7550 Case, SL7580 Case, SL7590 Cases