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 (
    86300, 86326, 86270, 86291, 86299, 86325, 
    86269, 86290, 86292, 86318, 86346, 
    86350, 86256, 86309, 86298, 86324, 
    86311, 86327, 86260, 86308, 86268, 
    86289, 86304, 86317, 86347, 86351, 
    86344, 86348, 86303, 86316, 86254, 
    86306, 86312, 86328, 86345, 86349, 
    86273, 86305, 86296, 86322, 86340, 
    86341, 86266, 86287, 86294, 86320, 
    86264, 86285
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00109

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (86300,86326,86270,86291,86299,86325,86269,86290,86292,86318,86346,86350,86256,86309,86298,86324,86311,86327,86260,86308,86268,86289,86304,86317,86347,86351,86344,86348,86303,86316,86254,86306,86312,86328,86345,86349,86273,86305,86296,86322,86340,86341,86266,86287,86294,86320,86264,86285)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
86254 nuie Revive Double Panel Designer Radiator 1800 x 354mm - High Gloss White
86256 nuie Revive Vertical Double Panel Radiator 1800 x 528mm - High Gloss White
86260 nuie Revive With Mirror Double Panel Radiator With Mirror 1800 x 499mm - High Gloss White
86264 nuie Revive Horizontal Double Panel Radiator 600 x 412mm - High Gloss White
86266 nuie Revive Horizontal Double Panel Radiator 600 x 586mm - High Gloss White
86268 nuie Revive Horizontal Double Panel Radiator 600 x 992mm - High Gloss White
86269 nuie Revive Horizontal Double Panel Radiator 600 x 1398mm - High Gloss White
86270 nuie Revive Horizontal Double Panel Radiator 600 x 1572mm - High Gloss White
86273 nuie Revive Double Panel Designer Radiator 1500 x 354mm - High Gloss White
86285 nuie Revive Horizontal Double Panel Radiator 600 x 412mm - Anthracite
86287 nuie Revive Horizontal Double Panel Radiator 600 x 586mm - Anthracite
86289 nuie Revive Horizontal Double Panel Radiator 600 x 992mm - Anthracite
86290 nuie Revive Horizontal Double Panel Radiator 600 x 1398mm - Anthracite
86291 nuie Revive Horizontal Double Panel Radiator 600 x 1572mm - Anthracite
86292 nuie Sloane Vertical Double Panel Radiator 1800 x 528mm - Anthracite
86294 nuie Sloane Horizontal Double Panel Radiator 600 x 412mm - Anthracite
86296 nuie Sloane Horizontal Double Panel Radiator 600 x 586mm - Anthracite
86298 nuie Sloane Horizontal Double Panel Radiator 600 x 992mm - Anthracite
86299 nuie Sloane Horizontal Double Panel Radiator 600 x 1398mm - Anthracite
86300 nuie Sloane Horizontal Double Panel Radiator 600 x 1572mm - Anthracite
86303 nuie Sloane Vertical Double Panel Radiator 1500 x 354mm - Anthracite
86304 nuie Sloane Double Panel Designer Radiator 1800 x 354mm - Anthracite
86305 nuie Revive Double Panel Designer Radiator 1500 x 354mm - Anthracite
86306 nuie Revive Double Panel Designer Radiator 1800 x 354mm - Anthracite
86308 nuie Revive With Mirror Double Panel Designer Radiator 1800 x 499mm - Anthracite
86309 nuie Revive Vertical Double Panel Radiator 1800 x 528mm - Anthracite
86311 nuie Sloane Double Panel Designer Radiator 1800 x 381mm - Anthracite
86312 nuie Xcite Xcite Designer Radiator 1775 x 450mm - Anthracite
86316 nuie Sloane Double Panel Designer Radiator 1500 x 354mm - Satin White
86317 nuie Sloane Double Panel Designer Radiator 1800 x 354mm - Satin White
86318 nuie Sloane Vertical Double Panel Radiator 1800 x 528mm - Satin White
86320 nuie Sloane Horizontal Double Panel Radiator 600 x 412mm - Satin White
86322 nuie Sloane Horizontal Double Panel Radiator 600 x 586mm - Satin White
86324 nuie Sloane Horizontal Double Panel Radiator 600 x 992mm - Satin White
86325 nuie Sloane Horizontal Double Panel Radiator 600 x 1398mm - Satin White
86326 nuie Sloane Horizontal Double Panel Radiator 600 x 1572mm - Satin White
86327 nuie Sloane Double Panel Designer Radiator 1800 x 381mm - Satin White
86328 nuie Xcite Xcite Designer Radiator 1775 x 450mm - High Gloss White
86340 nuie Revive Compact Designer Radiator 1800 x 237mm - High Gloss White
86341 nuie Revive Compact Designer Radiator 1800 x 237mm - Anthracite
86344 nuie Salvia Designer Radiator 1800 x 383mm - High Gloss White
86345 nuie Salvia Designer Radiator 1500 x 383mm - High Gloss White
86346 nuie Salvia Designer Radiator 635 x 1223mm - High Gloss White
86347 nuie Salvia Designer Radiator 635 x 863mm - High Gloss White
86348 nuie Salvia Designer Radiator 1800 x 383mm - Anthracite
86349 nuie Salvia Designer Radiator 1500 x 383mm - Anthracite
86350 nuie Salvia Designer Radiator 635 x 1223mm - Anthracite
86351 nuie Salvia Designer Radiator 635 x 863mm - Anthracite