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 (
    5531, 5528, 5525, 5521, 5526, 5515, 5501, 
    5529, 5503, 5512, 5514, 5511, 5523, 
    5513, 5516, 5524, 5518, 5527, 5519, 
    5532, 5530, 5517, 6766, 6730
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00038

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": 24,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (5531,5528,5525,5521,5526,5515,5501,5529,5503,5512,5514,5511,5523,5513,5516,5524,5518,5527,5519,5532,5530,5517,6766,6730)",
      "attached_condition": "cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text
5501
5503
5511
5512
5513
5514
5515
5516
5517
5518
5519
5521 <p>P10-2UH1-C5-001 - 450-512 MHz 2-5 In, 100 Out, 13.8V 25A Amplifier</p>
5523 <p>P10-10UH1-C5-001 - 450-512 MHz 10-20 In, 100 Out, 13.8V 25A Amplifier</p>
5524
5525
5526
5527
5528
5529
5530
5531
5532
6730
6766