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, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    10566, 10567, 10572, 10575, 10581, 10582, 
    10583, 10584, 10588, 10589, 10590, 
    10595, 10596, 10602, 10612, 10613
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00097

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id", "idx_product_lang"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 16,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (10566,10567,10572,10575,10581,10582,10583,10584,10588,10589,10590,10595,10596,10602,10612,10613) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description unit_name
10566 Housing cover - outer side rear view mirror, left<p>Part number 87615T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10567 Scalp-out side rear view mirror, left<p>Part number 87616T1000MDY</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10572 Housing cover - outer side rear view mirror, right<p>Part number 87625T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10575 Scalp-out side rear view mirror, right<p>Part number 87626T1000MDY</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10581 Garnish assembly-front door side, left<p>Part number 87721T1001</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10582 Garnish assembly - front door side right<p>Part number 87722T1001</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10583 Garnish assembly - rear door side left<p>Part number 87731T1001</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10584 Garnish assembly-rear door side, right<p>Part number 87732T1001</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10588 Glass & Molding Assembly - Quarter Fixt, Left<p>Part number 87810T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10589 Glass and Molding Assembly - Quarter Fixt, Right<p>Part number 87820T1100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10590 nut assembly<p>Part number 878183N000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10595 Buckle Assembly - Front Seat Belt Driver's Side<p>Part number 88830T1000OWN</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10596 Buckle Assembly - Front Seat Belt Passenger Seat<p>Part number 88840T1000OWN</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10602 screw-tapping<p>Part number 1243805163</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10612 Nut-Seat Belt<p>Part number 89822D2000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10613 strap<p>Part number 1799313000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>