SELECT 
  cscart_ult_product_descriptions.product_id, 
  cscart_ult_product_descriptions.short_description, 
  IF(
    cscart_ult_product_descriptions.short_description = "", 
    cscart_ult_product_descriptions.full_description, 
    ""
  ) AS full_description, 
  cscart_ult_product_descriptions.meta_keywords, 
  cscart_ult_product_descriptions.meta_description, 
  cscart_ult_product_descriptions.search_words, 
  cscart_ult_product_descriptions.promo_text 
FROM 
  cscart_ult_product_descriptions 
WHERE 
  cscart_ult_product_descriptions.product_id IN (
    6340, 6244, 6345, 6343, 6341, 6346, 6344, 
    6342
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'en'

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_ult_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id", "company_id"],
      "key": "product_id",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 8,
      "filtered": 100,
      "index_condition": "cscart_ult_product_descriptions.product_id in (6340,6244,6345,6343,6341,6346,6344,6342)",
      "attached_condition": "cscart_ult_product_descriptions.company_id = 1 and cscart_ult_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text
6244
6340 VHF narrow band antenna only 136-174 MHz
6341 Kit with UHF SUPERBAND antenna 340-512 MHz
6342 UHF SUPERBAND antenna only 340-512 MHz
6343 Kit with 800 MHz SUPERBAND antenna 806-896 MHz
6344 800 MHz SUPERBAND antenna only 806-896 MHz
6345 <p>Kit with dual band antenna 150-174 & 380-512 MHz</p>
6346 150-174/380-512/760-870MHz