Optimizing calculations of historical data

I'm currently just using Redis to record flight pricing info so

id | flight no | date | ticket class | cost

this gets updated 1-2 times a day so for flight UA1545 for example would have thousands of data points over the past year on it's pricing.

The queries are a bit slow in calculating whether or not a user is getting a good price for a ticket given how far out or soon he's booking. Based on that, what kind of db engine and optimizations do you think I should be looking at?