They're at Epcot where Futureworld meets World Showcase ... the noman's land between Mexico and Canada.

They're at a "permanent" food cart that also sells, hot dogs, beer, and pop corn. According to Allears, it's called "Promenade Refreshments." The line can be long - but so worth those pretzels!
I remember them at DHS too near Indiana Jones, but that was a few years back.