In an old tweet from Mearls, he states the Dungeon Master Guide would contain a "quick progression XP table" (as well as a slow progression, by the way). However, the section Experience Points (p. 260) of the DMG has nothing of sorts, and I do not remember seeing anything like that in the DMG. Instead, we have alternative ways of rewarding experience or levels, such as Milestones, but these aren’t clearly "slower" or "faster", they are entirely different approaches. Similarly, the other book that has lots of DM tools, Xanathar Guide’s to Everything, also does not contain any information on alternative slower/faster progressions (at least I could not find any).
However, a fast/slow, official/playtested table would still be interesting, from my point-of-view. There were campaigns where I wanted the PCs to level a little bit slower, and others I wanted them to level faster, and then I would just guess some numbers that made sense for me and work on it on the run, which is not the best approach for a problem usually.
So, is there any published table on Experience/Level, or, equivalently, Experience/CR (i.e., in a quick progression style, monsters with the same CR would reward more experience, and in a slower mode, less experience)? If not, was something like this printed in any Unearthed Arcana, at least?