Reddit reviews Leze - Ultra Thin Keyboard Skin Cover for ASUS UX501 K501UX F554LA F555LA F555UA F556UA R556LA X540SA X552 X555DA GL502VY GL502VS GL702VM GL702VS GL552VW GL752VW GL552JX Q504UA Q534UX Q524UQ - Black
We found 1 Reddit comments about Leze - Ultra Thin Keyboard Skin Cover for ASUS UX501 K501UX F554LA F555LA F555UA F556UA R556LA X540SA X552 X555DA GL502VY GL502VS GL702VM GL702VS GL552VW GL752VW GL552JX Q504UA Q534UX Q524UQ - Black. Here are the top ones, ranked by their Reddit score.
Extra slim silicone skin, made it easier for typingClosely paste the keyboard surface and fitted each key perfectlySoft durable ultra thin material to ensure comfortable usage while typingRemovable and washable, keeping it clean and makes it always newWaterproof and dustproof, protect your laptop against spills, dust, and other contaminants
So i dont think there is a special cover just for the WASD keys, but alas I have found this. https://www.amazon.com/Leze-Keyboard-GL502VY-GL502VS-GL702VM/dp/B01NBR6B3M/ref=sr_1_3?s=electronics&ie=UTF8&qid=1509672043&sr=1-3&keywords=ROG-GL552VW+keyboard+cover
I think this is as close as you are going to get.