If you really want to have an embedded MySQL, you can use golangs C bindings to integrate with: https://dev.mysql.com/doc/refman/5.1/en/libmysqld.html. I haven't seen any project packing up the bindings for this in a nice Go package, that would be an interesting small project.
Otherwise you can use Docker to set up a throwaway MySQL server, this requires some setup/teardown steps before you run go test though. This is what we are doing where I work.
In both cases, you will need to write setup/teardown methods that creates and drops tables as needed for your tests. These are just normal SQL statements, DROP DATABASE, CREATE TABLE etc.
Testify https://github.com/stretchr/testify has tooling for setup/teardown, but just writing a helper function for this works just fine.