i have a set of earplugs that have 32 decibel reduction rating. However i could still hear stuff with it on. So you might want to try something higher if you could find it. I know they have like 35 db rating. not sure if there's anything higher. Just go to your local pharmacy like CVS, Rite Aid, or supermarket and just buy some, not that expensive. I got my 10 pair for like $3.
Same situation I was in, I went to Advanced Auto Parts and bought me a set of ear plugs[$2 for like 10] that you roll up into a thin cone[less than 1"] and since its like a sponge material once you insert it into your ear it starts expanding and blocking out everything👍, it really did help me. And during the real DAT you can't bring your own set, those big earmuffs were uncomfortable, and besides you won't need them everyone is taking a test too.
Don't remember the brand...
just make sure on the box it says that it does reduce noise[30db or more], and I think the one I used reduced about 30 decibels <--more than enough.