I am not sure that MySQL can handle this is an easy way. At least, it's not part of the standard implementation of MySQL nor MariaDB. You can check Protect Your Data: Row-level Security in MariaDB 10.0 for a solution involving stored procedures. I guess it can be applied to not only MariaDB, but also to MySQL.
If you have the option, you can check PostgreSQL and how you can define Row Level Policies. These policies align very well with your needs; and might provide a much better match.
You can see on this part documentation one use-case which matches yours:
To allow all users to access their own row in a users table, a simple policy can be used:
CREATE POLICY user_policy ON users
USING (user_name = current_user);
(user_name would be equivalent to your accountID).
Although this is not a full answer, I hope it helps.