是否有可能进一步优化这些SQL查询?

I have a Rails app (running on a Heroku account) which is grabbing a bunch of statistics for the home page regarding the number of records which match certain criteria. Each count is displayed as a number on the page. My table (listings) consists of about 22,500 records. On production it takes the page about 350ms to load (still below the threshold but not great for a home page).I have a Rails app (running on a Heroku account