That is kind of strange. No other region has experienced any surge whatsoever in the past 3 days (
https://wowtoken.info/) but Europe experienced a +30k bump over the course of ~3 hours. No new events or official announcements.
Maybe more boosts being sold as we get closer to BfA? Players can store one up for a new allied race and there may be some drive to use them in the coming weeks while prices remain relatively low and people begin to realize that Blizz killing the automated group finder features on WQs makes invasion leveling through Legion much more difficult (which I believe is coming with the pre-patch). Or players buying tokens for gametime thinking that pre-patch already hit or will hit on Tuesday?