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 (
    20765, 20766, 20767, 20768, 20769, 20770, 
    20771, 20772, 20773, 20774, 20775, 
    20776, 20777, 20778, 20779, 20780
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00954

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 (20765,20766,20767,20768,20769,20770,20771,20772,20773,20774,20775,20776,20777,20778,20779,20780) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description unit_name
20765 Coupler-Front View Camera<p>Part number 99216JI010</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20766 Emblem-GENESIS<p>Part number 86300T1100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20767 Grille Assembly - Radiator<p>Part number 86350T1030</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20768 Cover assembly - upper radiator grille<p>Part number 86390T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20769 Cover Assy-SCC Unit<p>Part number 86380T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20770 Bracket-front bumper side, left<p>Part number 86551T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20771 Bracket - front bumper side, right<p>Part number 86552T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20772 Clip-front bumper side mounting<p>Part number 865183M000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20773 Molding-Front Bumper License Plate<p>Part number 86519T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20774 Absorber-Front Bumper Energy<p>Part number 86520T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20775 Molding assembly - bumper, lower part<p>Part number 86569T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20776 Stiffener Assembly - Front Bumper Lower<p>Part number 86570T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20777 Antinoise Pad - Front Bumper<p>Part number 86523T1100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20778 Antinoise pad-bumper molding, center<p>Part number 86522T1100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20779 Holder-parking assist system NO.4<p>Part number 86584T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
20780 End piece - air duct, left<p>Part number 86545T1100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>