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 (
    8450, 8451, 8456, 8459, 8462, 8464, 8466, 
    8470, 8476, 8477, 8478, 8479, 8490, 
    8491, 8498, 8499
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00036

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 (8450,8451,8456,8459,8462,8464,8466,8470,8476,8477,8478,8479,8490,8491,8498,8499) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description unit_name
8450 bolt<p>Part number 1142106186B</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8451 dynamic damper<p>Part number 81726E7000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8456 Trim assembly - tailgate frame side, left<p>Part number 81730G9500NNB</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8459 Trim Assembly - Tailgate Frame Side, Right<p>Part number 81740G9500NNB</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8462 Drive unit assembly - power tailgate, right<p>Part number 81840G9510</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8464 Counter balance & bracket assembly-power tailgate, left<p>Part number 81830G9510</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8466 Weatherstrip Assy-Tail Gate Pinch, Left<p>Part number 81850G9510</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8470 Wiring-front door trim integration, left<p>Part number 26171G9010</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8476 Weather strip assembly-rear door side, right<p>Part number 83140G9500</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8477 plug-hole<p>Part number 83191G9001</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8478 Weather strip assembly-rear door belt outside, left<p>Part number 83210G9500</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8479 Weather strip assembly - rear door belt outside, right<p>Part number 83220G9500</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8490 Glass assembly - rear door fixed, left<p>Part number 83570G9520</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8491 Glass assembly - rear door fixed, right<p>Part number 83580G9530</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8498 Motor assembly - power window regulator rear, left<p>Part number 83450G9800</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
8499 Motor assembly - power window regulator rear, right<p>Part number 83460G9800</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>