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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    87201, 87218, 90801, 85014, 85020, 85026, 
    85032, 87182, 87199, 87216, 90799, 
    87154, 87155, 87156, 87157, 87158, 
    87159, 87287, 87180, 87197, 87214, 
    85018, 85024, 85030
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00086

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.82"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.42",
        "eval_cost": "2.40",
        "prefix_cost": "10.82",
        "data_read_per_join": "91K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (87201,87218,90801,85014,85020,85026,85032,87182,87199,87216,90799,87154,87155,87156,87157,87158,87159,87287,87180,87197,87214,85018,85024,85030)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
85014 Hudson Reed Solar Floor Standing 2 Drawer Vanity Cabinet 800mm - Pure White
85018 Hudson Reed Solar Wall Hung 2 Drawer Vanity Cabinet 800mm - Pure White
85020 Hudson Reed Solar Floor Standing 2 Drawer Vanity Cabinet 800mm - Cool Grey
85024 Hudson Reed Solar Wall Hung 2 Drawer Vanity Cabinet 800mm - Cool Grey
85026 Hudson Reed Solar Floor Standing 2 Drawer Vanity Cabinet 800mm - Indigo Blue
85030 Hudson Reed Solar Wall Hung 2 Drawer Vanity Cabinet 800mm - Indigo Blue
85032 Hudson Reed Solar 800mm Floor Standing 2-Drawer Unit - Fern Green
87154 Old London 1000mm Rectangle Marble Top/Basin - 1 Tap Hole - Black
87155 Old London 1000mm Rectangle Marble Top/Basin - 1 Tap Hole - White
87156 Old London 1000mm Rectangle Marble Top/Basin - 1 Tap Hole - Grey
87157 Old London 1000mm Rectangle Marble Top/Basin - 3 Tap Hole - Black
87158 Old London 1000mm Rectangle Marble Top/Basin - 3 Tap Hole - White
87159 Old London 1000mm Rectangle Marble Top/Basin - 3 Tap Hole - Grey
87180 Old London Floor Standing 2 Door Basin Unit 600mm - Storm Grey
87182 Old London Floor Standing 2 Door Basin Unit 800mm - Storm Grey
87197 Old London Floor Standing 2 Door Basin Unit 600mm - Twilight Blue
87199 Old London Floor Standing 2 Door Basin Unit 800mm - Twilight Blue
87201 Old London Floor Standing 2 Door Basin Unit 1000mm - Twilight Blue
87214 Old London Floor Standing 2 Door Basin Unit 600mm - Timeless Sand
87216 Old London Floor Standing 2 Door Basin Unit 800mm - Timeless Sand
87218 Old London Floor Standing 2 Door Basin Unit 1000mm - Timeless Sand
87287 Old London Components Single Bowl Marble Worktop Top 1 Tap Hole, 1000mm - White
90799 Old London 800mm 2-DOOR BASIN UNIT - Hunter Green
90801 Old London 1000mm 2-DOOR BASIN UNIT - Hunter Green