Wow, man, I feel for you! My situation was almost like this, although since mine had about 2100 miles, it was nearly worn out compared to this one!
Mine was listed as a "manufacturer's vehicle," but I don't see even that on yours. You could try AutoCheck, but they do tend to duplicate each other--probably the odds are against getting anything much new.
So, assuming the dealer is OK with it, I'd definitely spend the money on a professional inspection. Drive it as far as you can, and pay attention to idle & braking--I think I've detected some issues related to low-usage on mine: rough idle (carbon deposits?) and vibration on braking. The latter was easily fixed with a rotor turn, but I don't know how fixable the former is. Also, watch for flat-spotting on the tires. By what I read here, the Hankooks that came on the '15s were prone to that if not used regularly. And is this a Kia dealer? If so, ask if you get the whole 100,000 mile warranty, or only the 60K one.
I do think that price is a touch high for a '15 at this point, even with super-low mileage. I'd assume there's some room to negotiate there.
Let us know what you decide to do!
2016 V8 VIP+, black with white interior