Hello,

I could suggest first adding some extra RAM to your Droplet to make sure that you have enough for the other services as well, after that you could take a look at this answer here on how to tweak your MySQL database:

https://www.digitalocean.com/community/questions/how-to-tweak-mysql-mariadb-configuration-for-increased-performance-and-stability

Also another thing that you could consider is using the DigitalOcean Managed MySQL databases which would allow you to quickly and easily spin up a high-performance MySQL cluster:

https://www.digitalocean.com/products/managed-databases-mysql/

Hope that this helps!
Regards,
Bobby