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 (
    92229, 92230, 92231, 92237, 92469, 92470, 
    92471, 85585, 91892, 92150, 92197, 
    92457, 92240, 92245, 92247, 92248, 
    92249, 92250, 92252, 92253, 92485, 
    92486, 92487, 85578
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00067

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 (92229,92230,92231,92237,92469,92470,92471,85585,91892,92150,92197,92457,92240,92245,92247,92248,92249,92250,92252,92253,92485,92486,92487,85578)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
85578 Shallow Seal Trap
85585 Classic Exposed Bath Waste & Overflow
91892 BC Designs Victrion 3 Tier Towel Rack - Chrome
92150 BC Designs Standpipes Traditional Bath Legs with Adjustable Shrouds - Chrome
92197 BC Designs Bath Wastes Push Down Concealed Bath Waste - Chrome
92229 BC Designs Bath Wastes Push Down Bath Waste 60mm (Unslotted) - Brushed Nickel
92230 BC Designs Bath Wastes Push Down Bath Waste 60mm (Unslotted) - Black Silk
92231 BC Designs Bath Wastes Push Down Bath Waste 60mm (Unslotted) - Copper
92237 BC Designs Bath Wastes Push Down Bath Waste 60mm (Unslotted) - Nickel
92240 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Powder Blue
92245 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Light Fawn
92247 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Gunmetal
92248 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Industrial Grey
92249 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Khaki Green
92250 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Mushroom
92252 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Powder Grey
92253 BC Designs Basin Wastes Push Down Basin Waste (Unslotted) - Satin Rose
92457 BC Designs Exposed Bath Trap With Adapter (40/42mm) - Chrome
92469 BC Designs Push Down Bath Waste 60mm (Unslotted) - Brushed Chrome
92470 BC Designs Push Down Bath Waste 60mm (Unslotted) - Brushed Copper
92471 BC Designs Push Down Bath Waste 60mm (Unslotted) - Gold
92485 BC Designs Push Down Basin Waste (Unslotted) - Marble
92486 BC Designs Push Down Basin Waste (Unslotted) - Matt White
92487 BC Designs Push Down Basin Waste (Unslotted) - Polished White