We went really deep on this recently, as we looked to migrate off Keen.io for that exact reason (only time based queries, also it's really slow).

We didn't look at MongoDB due to too many people on the team having been burned by it in the past, but after looking at a lot of stuff we settled on Redshift with a Postgres database in front of it using dblink and foreign data wrapper. This allowed us to have extremely fast reads of common queries with only a 5 minute lag on data becoming available.

It's amazing what you can build with Postgres. I might write up a blog post about our exact strategy if that would be interesting to people.