如何改进lrge表在低规格系统上的MySQL性能?

I have a Raspberry Pi I have been using to log household temperature data collected from a bunch of 1-Wire sensors. The data has all been collected into a MySQL database over several years. I use the Raspbian distribution and the default MySQL configuration. I now have a table with over a million records and my Pi is running queries very slowly.I have a Raspberry Pi I have been using to log