Can you get a mastery 7 token in hexakill

I don't know if it was always the case, but their stance at this point is they want rank 6/7 mastery tokens to represent skill in the competitive SR environment. It might be that they worked in alternative game modes briefly, but as of the announcement that they'd have mastery in ARAM/TT (or perhaps the mastery update prior to that), it's only regular SR (so normals or ranked, but no special modes) for the mastery tokens (although you'll be able to get mastery points and level up to 5 wherever).

I know I got one of my tokens for Lulu from DnD. Since then Riot has definitively stated that they intend for tokens to only be awarded from SR, but perhaps they hadn't yet set that limit when we got our tokens.