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 (
    21407, 21408, 21409, 21410, 21411, 21412, 
    21413, 21414, 21415, 21416, 21417, 
    21418, 21419, 21420, 21421, 21422
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.01000

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 (21407,21408,21409,21410,21411,21412,21413,21414,21415,21416,21417,21418,21419,21420,21421,21422) and cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id short_description full_description unit_name
21407 lever-foot<p>Part number 97168T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21408 cam-mode<p>Part number 97212T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21409 lever-foot<p>Part number 97168T6050</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21410 cam-mode<p>Part number 97212T6050</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21411 Door assembly (A) - air inlet<p>Part number 971A1T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21412 Door Assembly - Air Inlet<p>Part number 971A1T6010</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21413 Door assembly - air inlet (A)<p>Part number 971A1T6020</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21414 Door assembly (B) - air inlet<p>Part number 971A1T6030</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21415 Seal-ventilator<p>Part number 971A2T6020</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21416 blower unit<p>Part number 97100T6100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21417 Heater & Evaporator Assembly<p>Part number 97205T6310</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21418 Arm-vent door<p>Part number 97224T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21419 Door Assembly - Floor<p>Part number 97148T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21420 Lever-ventilator door<p>Part number 97309T6050</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21421 Case-Blower, Top<p>Part number 97111T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21422 Case - blower, lower part<p>Part number 97112T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>