To get more visibility we can colorize SLA field. Color could be depend on critical level. For example, we should use red color for blocker issues and blue color for new non-critical issues:
To define a custom color scheme we should go to the JIRA Administration/Plugins/HelpDesk/SLA settings:
In the scheme we can add color rules for each critical level:
To define a specific color for overdue tasks (remaining time is already negative = spent time is bigger than SLA interval) we should define a big negative number.
Now we must do association the custom color scheme with a specific SLA field. To do it, go to the Custom Fields menu and find our SLA field. After that choose a custom color scheme: