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 (
    25335, 25336, 25337, 25338, 25339, 25340, 
    25341, 25342, 25343, 25344, 25345, 
    25346, 25347, 25348, 25349, 25350
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00151

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 (25335,25336,25337,25338,25339,25340,25341,25342,25343,25344,25345,25346,25347,25348,25349,25350) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description unit_name
25335 Tube Assembly - ICCU<p>Part number 364T01XFA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25336 inverter assembly<p>Part number 366011XCA5</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25337 inverter assembly<p>Part number 366011XCM5</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25338 Pad - sound absorption<p>Part number 364081XCA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25339 Pad - sound absorption<p>Part number 366601XAA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25340 Cover assembly-input<p>Part number 366A71XAA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25341 Gasket-Output<p>Part number 366G11XAA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25342 Cover-Input<p>Part number 366A71XAM0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25343 Gasket-Output<p>Part number 366G11XAM0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25344 Gasket - Inverter<p>Part number 366G91XAA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25345 Gasket - Inverter<p>Part number 366G91XAM0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25346 BOLT<p>Part number 366H51X147</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25347 Tube Assembly - Front<p>Part number 366T01XFA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25348 Tube assembly-rear<p>Part number 366T21XCA0</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25349 VCU unit<p>Part number 397511XJD5</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
25350 Bracket-VCU<p>Part number 397611X001</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>