LFD kills MySQL every hour because the binary from CloudLinux is not installed in the same path as the cPanel MySQL. However, LFD won't kill anything unless the option PT_USERKILL is enabled, which is strongly recommended not to be enabled in the configuration file:
Warning: We don't recommend enabling this option unless absolutely necessary, as it can cause unexpected problems when processes are suddenly terminated. It can also lead to system processes being terminated, which could cause stability issues. It is much better to leave this option disabled and to investigate each case as it is reported when the triggers above are breached.
If you still need PT_USERKILL enabled, please add the following lines in /etc/csf/csf.pignore:
And then restart LFD.