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 (
    10818, 10820, 10821, 10822, 10825, 10828, 
    10829, 10831, 10836, 10839, 10841, 
    10849, 10851, 10855, 10864, 10867
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00454

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 (10818,10820,10821,10822,10825,10828,10829,10831,10836,10839,10841,10849,10851,10855,10864,10867) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description unit_name
10818 Motor & Link Assembly - Windshield Wipers<p>Part number 98100T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10820 Arm assembly - windshield wiper (driver's side)<p>Part number 98311T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10821 Arm assembly - windshield wiper (passenger seat)<p>Part number 98321T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10822 Rubber assembly - wiper blade (driver's seat)<p>Part number 98351B1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10825 Rubber assembly - wiper blade (passenger seat)<p>Part number 98361F2500</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10828 clip-hose<p>Part number 1472024006</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10829 Funnel assembly<p>Part number 98616T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10831 Filter-Washer Motor<p>Part number 985151F000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10836 Insulation<p>Part number 97258D2400</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10839 blower unit<p>Part number 97100T1100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10841 Arm-vent door<p>Part number 97183T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10849 Arm-Flower Door<p>Part number 97185B1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10851 Case-intake<p>Part number 97121T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10855 Seal-intake<p>Part number 97127T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10864 Cover-Heater Core<p>Part number 97141T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
10867 separator<p>Part number 97206T1000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>