My suggestion is to try TokuDB storage engine on that table. Our (admittedly text heavy) workload got order of magnitude scalability improvements and a dramatic fall in query times.
I tried Tokudb as well and below are the stats comparison for complex SUM and COUNT query.
Please note that the number of rows and size is exactly the same and there is a partition on a Date column
Table size 10GB and rows 12 Million
Also note that I am using the default settings of Tokudb
With Tokudb - 1 min 41.38 sec
With Innodb - 58.17 sec
Table size 10GB and rows 12 Million
Also note that I am using the default settings of Tokudb
With Tokudb - 1 min 41.38 sec With Innodb - 58.17 sec
So almost double.