Where I live, humidity can get low during much of the year. Care-Fresh compounds the problem in my case because it sucks the moisture out of everything touching it.
I've tried misting it and reducing ventilation. That helps. Still, consider that if the snake is a baby, baby kingsnakes have thin skin and are moisture loss sensitive. An adult snake will probably be just fine on it.
It is inert, so that is good. It does have dust just like pretty much any particulate substrate, so don't think it is dust-free.
No harm in starting with a small amount and seeing how it works out.
I'm crazy because I try Care-Fresh again every once in awhile expecting a different result. Hognose do fine on it, so do rosies. I just don't like it for kings and milks for the above reasons. But try for yourself. Might be fine under your conditions.
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Mark