You don't say where you are but the best I can do is suggest Chlorophorus varius.
Here is a bit of info
I am no particular expert on beetles, but I do have seven snakes. Longhorn beetles usually eat wood so probably came in on the substrate. This particular species eats sweet chestnut wood!! I cannot see how they could harm the snake. In the old days I always microwaved my substrate and then let it cool before I put it in with the snakes. That way any beasties would be killed off, including bacteria which I was more worried about than I would have been with Beetles.