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 (
    21053, 21054, 21055, 21056, 21057, 21058, 
    21059, 21060, 21061, 21062, 21063, 
    21064, 21065, 21066, 21067, 21068
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00038

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 (21053,21054,21055,21056,21057,21058,21059,21060,21061,21062,21063,21064,21065,21066,21067,21068) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}

Result

product_id short_description full_description unit_name
21053 Bracket-windshield molding mounting, right<p>Part number 86147T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21054 Cover Assembly - Cowl Top<p>Part number 86150T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21055 Seal strip assembly - hood side, left<p>Part number 86470T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21056 Seal Strip Assembly-Hood Side, Right<p>Part number 86480T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21057 Garnish assembly-left<p>Part number 86130T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21058 Garnish assembly-right<p>Part number 86140T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21059 Stopper-rear window glass<p>Part number 871143K000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21060 Coupler-Front View Camera<p>Part number 99216T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21061 Tapping screw - flange head<p>Part number 1249204127B</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21062 Tapping screw - flange head<p>Part number 1249204127E</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21063 Tapping screw - flange head<p>Part number 1249305167B</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21064 Emblem-GENESIS<p>Part number 86300T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21065 Grille assembly - radiator, center<p>Part number 86353T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21066 Cover - radiator grill, back<p>Part number 86366T6010</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21067 Bracket-Radiator Grille<p>Part number 86352T6010</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>
21068 Chrome Piece 1 Radiator<p>Part number 86354T6000</p><p>If you are not sure about compatibility, please contact us in advance to confirm the part number.</p>