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 (
    18365, 18366, 18367, 18368, 18369, 18370, 
    18371, 18372, 18373, 18374, 18375, 
    18376, 18377, 18378, 18379, 18380
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00037

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 (18365,18366,18367,18368,18369,18370,18371,18372,18373,18374,18375,18376,18377,18378,18379,18380) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description unit_name
18365 stopper-bumper<p>Part number 55326J5000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18366 spring-rear<p>Part number 55330G9150</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18367 Bolt-Washer Assembly<p>Part number 1145710356K</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18368 Cover - rear low arm, left<p>Part number 55230J5100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18369 Crossmember Complete-Rear<p>Part number 55405G9300</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18370 Wheel Assembly - Steering<p>Part number 56110G9NC0DUE</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18371 Body-steering wheel<p>Part number 56120G9550DUE</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18372 Extension wire (left)<p>Part number 56190G9330</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18373 Bezel-Switch<p>Part number 96750G9000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18374 Switch Assembly - Steering Remote Control<p>Part number 96700G9190NNB</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18375 Switch assembly - steering remote control left<p>Part number 96710G9190NNB</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18376 Switch assembly - steering remote control right<p>Part number 96720G9040NNB</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18377 Switch assembly - paddle shifters, left<p>Part number 96770G9005</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18378 Switch assembly - paddle shifters, right<p>Part number 96780G9005</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18379 bolt<p>Part number 1127608201</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
18380 Nut-Flange<p>Part number 1337608003</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>