> I forgot to mention PG. I have put small analytic datasets, 80 million rows or so, in Postgres with good results, but even then the response time was never less than a few seconds

There is already a bewildering number of options in this space, but did you try TimescaleDB (a time-series extension for Postgres)?

I'm using it with 100 million plus rows, and aggregate queries return in less than 100ms, even on my laptop - it really is very impressive.

I haven't used them yet, but it also supports continuous aggregates (automatic roll ups), which would make common queries near instantaneous.