If you do not do any activity in your PHPMyAdmin it will log out automatically after 1440 seconds or say 24 minutes and shows error as "No activity within 1440 seconds, please log in again". This feature is not available in old versions of PHPMyAdmin. If you are working on your local environment it is very annoying to logging again and again. So to over come, you can increase your log out time with some greater value.
Follow below steps to update your log out time:
1) Go to your phpMyAdmin and login.
2) Now navigate to "settings" tab from the top.
3) Now you will see few more sub menu items. Click on "Features".
4) On this page select "General" tab (which is default tab).
5) Now update the "Login cookie validity" value, so your log out time will increase.
6) Update the value and click on "Apply" button. Note: PhpMyAdmin will take the new value as a log out time. But if any case it is not working try to restart the MySQL services. PhpMyAdmin Documentation Reference. See the screen shot below:
PhpMyAdmin version: 4.6.4