Have you tried squashing one on a white paper towel? Snake mites are usually full of blood, so when squished, you'll have a blood spot on the paper. That looks more like a wood mite of some kind to me? It has been a couple decades though, since I've personally had to deal with any on one of my snakes. I've been trying to find a good picture close-up of a snake mite to compare yours to. But if it's a wood mite, it had to come from somewhere, & if your substrate is only paper towels, I don't know where this would have come from?Snake mites can appear black, brown or reddish, btw. Use a damp white paper towel to wipe down your snakes- see if you find any on them...if so, they're probably snake mites. Wood mites shouldn't be interested in hitching rides on snakes. And when squished, there won't be blood from a "wood mite".
From Wiki-MaleOphionyssus natricis (snake mite)
excerpt: "The larvae are pale white. They either stay pale ivory or yellow if unfed in the protonymph stage. The mites turn a dark red if feeding does occur. After feeding, the mites have a soft body that is dark red or black in color and noticeable legs that can be seen by the human eye during the deutonymph stage."