MySQL: Queries limitations per host/user
Yes you can. You can create users with resource limits, e.g.:

mysql&gt; CREATE USER 'user_name'@'localhost' IDENTIFIED BY 'some_password'
    -&gt;     WITH MAX_QUERIES_PER_HOUR 20
    -&gt;          MAX_UPDATES_PER_HOUR 10
    -&gt;          MAX_CONNECTIONS_PER_HOUR 5
    -&gt;          MAX_USER_CONNECTIONS 2;


See here for more details:
https://dev.mysql.com/doc/refman/5.7/en/user-resources.html

Since every connection can run at most one query at a time, for the specific case you are describing, you probably want to set MAX_USER_CONNECTIONS to 100.