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 (152093, 152087) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00067

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "2.81"
    },
    "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": 2,
      "rows_produced_per_join": 2,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "2.41",
        "eval_cost": "0.40",
        "prefix_cost": "2.81",
        "data_read_per_join": "13K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (152093,152087)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
152087 <p>Giacca con Zip Intera Full Zipped Jacket</p>100% Poliestere Triacetato 100% Polyester Tricot Tasche laterali Pockets on sides Logo ricamato Embroidered logo Polsini in costina Rib cuff Zip sul retro Zip on the back<p>Colore blu: taglie disponibili , 3xs , 2xs</p><p>Colore blu royal :taglie disponibili xs , 2xs</p><p>Colore giallo: taglie disponibili , xs, 3xs</p>
152093 <p>Caratteristiche:<br /><br />Tessuto dalla massima tenuta con minimo peso<br />Loghi Givova ricamati<br />Giacca girocollo<br />Interno collo in costina<br />Giacche con zip intera<br />Tasche laterali<br />Tasche sui pantaloni<br />Elastan con Zip sul fondo dei pantaloni.</p><p>Colore Nero e rossa: taglia disponibile 3xs, xs</p><p>Colore nero e blu tuta visa turchese blu , taglie disponibili 5xs, 4xs,3xs</p>