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 (
    92026, 92034, 92114, 92122, 92501, 92502, 
    92503, 92504, 92505, 92506, 92507, 
    92192, 92193, 92194, 92195, 92196, 
    92204, 92205, 92206, 92207, 92208, 
    92209, 92442, 92443, 92448, 92147, 
    92148, 92149, 92349, 92350
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (92026,92034,92114,92122,92501,92502,92503,92504,92505,92506,92507,92192,92193,92194,92195,92196,92204,92205,92206,92207,92208,92209,92442,92443,92448,92147,92148,92149,92349,92350)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
92026 BC Designs Victrion Deck Mounted Crosshead Bath Shower Mixer - Chrome
92034 BC Designs Victrion Wall Mounted Crosshead Bath Shower Mixer - Chrome
92114 BC Designs Victrion Deck Mounted Lever Bath Shower Mixer - Chrome
92122 BC Designs Victrion Wall Mounted Lever Bath Shower Mixer - Chrome
92147 BC Designs Standpipes Traditional Cast Freestanding Bath Legs - 660mm x 40mm - Copper
92148 BC Designs Standpipes Traditional Cast Freestanding Bath Legs - 660mm x 40mm - Gold
92149 BC Designs Standpipes Traditional Cast Freestanding Bath Legs - 660mm x 40mm - Nickel
92192 BC Designs Bath Wastes Plug & Chain Exposed Ext Bath Waste - Brushed Chrome
92193 BC Designs Bath Wastes Plug & Chain Exposed Ext Bath Waste - Brushed Gold
92194 BC Designs Bath Wastes Plug & Chain Exposed Ext Bath Waste - Brushed Nickel
92195 BC Designs Bath Wastes Plug & Chain Exposed Ext Bath Waste - Gold
92196 BC Designs Bath Wastes Plug & Chain Exposed Ext Bath Waste - Nickel
92204 BC Designs Bath Wastes Push Down Exposed Bath Waste - Brushed Chrome
92205 BC Designs Bath Wastes Push Down Exposed Bath Waste - Brushed Gold
92206 BC Designs Bath Wastes Push Down Exposed Bath Waste - Brushed Nickel
92207 BC Designs Bath Wastes Push Down Exposed Bath Waste - Copper
92208 BC Designs Bath Wastes Push Down Exposed Bath Waste - Gold
92209 BC Designs Bath Wastes Push Down Exposed Bath Waste - Nickel
92349 BC Designs Standpipes 660x40 Freestanding Legs - Brushed Chrome
92350 BC Designs Standpipes 660x40 Freestanding Legs - Brushed Copper
92442 BC Designs Plug & Chain Exposed Bath Waste - Brushed Copper
92443 BC Designs Plug & Chain Exposed Bath Waste - Copper
92448 BC Designs Push Down Exposed Bath Waste - Brushed Copper
92501 BC Designs Extended Bath Filler - Brushed Chrome
92502 BC Designs Extended Bath Filler - Brushed Copper
92503 BC Designs Extended Bath Filler - Brushed Gold
92504 BC Designs Extended Bath Filler - Brushed Nickel
92505 BC Designs Extended Bath Filler - Copper
92506 BC Designs Extended Bath Filler - Gold
92507 BC Designs Extended Bath Filler - Nickel