I use these silicone caps on some hook eyes, and have them in the 3 smallest sizes, which covers most hooks that I use. https://hightempmasking.com/collections/high-temp-silicone-end-caps/products/3-32-id-high-temp-silicone-rubber-end-caps
I also use teflon tape, that I buy from Harbor Freight. I cut the tape into pieces at an angle, and, so they're about 3/8" long, and about 1/4" wide. That will cover the smaller hook eyes, even though it does require a bit of time to use the tape. I usually will paint a couple of hundred jigs at a time and will tape the eyes while watching TV, when I would not doing anything constructive anyway. The silicone caps & the teflon both are high heat resistant and the powder coat won't stick to either one of them.
I hang the jigs in my oven when coating, to heat them, and trying to grab a hook eye for me would be difficult, plus I can coat a lot in a short time, once the eyes are covered.
Some folks also use heat shrink tubing to cover the hook eye, but I've done some comparing of costs, it's too expensive for me, but may be cheaper for some folks. I can apply the teflon tape quickly now, once I figured out how to do it, and for the cost of the tape, I can cover around 10,000 jigs. Harbor Freight sells the tape in boxes of 10 rolls for around $9 and most other places sell it per roll for over $2 each.
Of course, folks use various methods to keep the powder out of the hook eye, and they can all work. It's just a matter of figuring out a method that works well for you, and doesn't cost you a fortune in either time or supplies.