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 (
    21999, 22000, 22001, 22002, 22003, 22004, 
    22005, 22006, 22007, 22008, 22009, 
    22010, 22011, 22012, 22013, 22014
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.01013

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 (21999,22000,22001,22002,22003,22004,22005,22006,22007,22008,22009,22010,22011,22012,22013,22014) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description unit_name
21999 Auto Transaxle and Torque Converter Assembly<p>Part number 450004JDF0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22000 BOLT-FLANGE<p>Part number 4735839100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22001 Carrier Assembly - Differential<p>Part number 530004J630</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22002 Disc-front wheel brake<p>Part number 51712T6300</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22003 BOLT<p>Part number 626173K200</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22004 nut<p>Part number 55159CU000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22005 nut<p>Part number 55259CU000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22006 Shock absorber assembly-front, left<p>Part number 54605T6960</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22007 spring-front<p>Part number 54630T6040</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22008 Shock Absorber Assembly-Front, Right<p>Part number 54606T6960</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22009 Shock Absorber Assembly - Rear<p>Part number 55307T6450</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22010 Crossmember-rear<p>Part number 55405T6100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22011 flange nut<p>Part number 626184R000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22012 Washer-Plain<p>Part number 51788T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22013 Plate-Lower Arm<p>Part number 55223T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
22014 BOLT-FLANGE<p>Part number 55117J5000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>