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 (
    86011, 86012, 86014, 86015, 86017, 86018, 
    86019, 86020, 86021, 86022, 86023, 
    86024, 86025, 86026, 86027, 86028, 
    86029, 86030, 86031, 86032, 86033, 
    86034, 86035, 86036
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00073

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 (86011,86012,86014,86015,86017,86018,86019,86020,86021,86022,86023,86024,86025,86026,86027,86028,86029,86030,86031,86032,86033,86034,86035,86036)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
86011 nuie Handles Finger Pull Handle 160mm Centres - Chrome
86012 nuie Handles Finger Pull Handle 224mm Centres - Chrome
86014 nuie Handles Square Drop Handle 32mm Centres - Chrome
86015 nuie Handles Indented Round Knob - Chrome
86017 nuie Handles 328mm D Handle Chrome - Chrome
86018 nuie Handles Square Strap Chrome Handle 128mm Centres - Chrome
86019 nuie Handles Finger Pull Handle 150mm - Chrome
86020 nuie Handles Finger Pull Handle 300mm - Chrome
86021 nuie Handles Finger Pull Handle 500mm - Chrome
86022 nuie Handles Round Strap Chrome Handle 128mm Centres - Chrome
86023 nuie Handles Art Deco Chrome Handle 160mm Centres - Chrome
86024 nuie Handles D Handle 150mm Centres - Chrome
86025 nuie Handles Slim Line D Handle 150mm Centres - Chrome
86026 Hudson Reed Handles Strap Handle 96mm Centres - Chrome
86027 Hudson Reed Handles D Handle 192mm Centres - Chrome
86028 Hudson Reed Handles Small Rear Fixed Handle 50mm Centres - Chrome
86029 nuie Handles Wrap Over Handle 50mm Centres - Matt Black
86030 nuie Handles D Handle 150mm Centres - Matt Black
86031 nuie Handles Slim Line D Handle 150mm Centres - Matt Black
86032 nuie Handles D Shape Bar Handle 210mm Centres - Matt Black
86033 nuie Handles D Shape Bar Handle 210mm Centres - Brushed Brass
86034 nuie Handles Bar Handle 155mm Centres - Matt Black
86035 nuie Handles Bar Handle 155mm Centres - Brushed Brass
86036 nuie Handles Wrap Over Handle 50mm Centres - Brushed Brass