That' a tough one. About 7-10 years ago there were plenty. Just about almost any spa in downtown/uptown Toronto, some in China Town, 75% of girls were quite young, meaning mostly under 35yo.
Now things have really changed a lot. Your best bet would be Sunrise to an extend (Tina comes to mind), Kawaii and Spring Green, though, I've only been there like 4 years ago, so things may have changed, wk. I've never been to Fantasy spa, so can't comment, but xtc27 and usefulidiot, for example, seem to recommend it.