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 (
    8326, 8328, 8333, 8342, 8343, 8344, 8345, 
    8355, 8356, 8362, 8365, 8366, 8367, 
    8368, 8370, 8371
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00042

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 (8326,8328,8333,8342,8343,8344,8345,8355,8356,8362,8365,8366,8367,8368,8370,8371) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description unit_name
8326 Unit assembly - rear corner radar, right<p>Part number 99150G9010</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8328 ECU-4WD<p>Part number 954474J350</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8333 Case-inlet duct<p>Part number 97121G9000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8342 compressor assembly<p>Part number 97701J5000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8343 Hose-Discharge<p>Part number 97762J5050</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8344 hose-suction<p>Part number 97763J5050</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8345 Panel Assembly-Bag<p>Part number 69100G9710</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8355 Extension assembly - quarter outer rear left<p>Part number 71550G9700</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8356 Extension assembly - quarter outer rear right<p>Part number 71560G9700</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8362 bolt<p>Part number 793593K100</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8365 bolt-connecting rod<p>Part number 2351325040</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8366 Bracket-Tensioner<p>Part number 252512CTA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8367 tensioner assembly<p>Part number 252812CTA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8368 Fan-cooling<p>Part number 252313R000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8370 blower assembly<p>Part number 25380J5000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8371 fan controller<p>Part number 25385D2000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>