The way you can exclude a certain file or folder(s) from the real time scanning is by adding a full UNC path of that particular file or folder(s).
Go to Filter Management tab from the cloud console.
Click on Edit to modify the the policy
Then go to Endpoint à Antivirus
Expand the Detection Settings
Add certain file(s) and/or folder(s)
Once finish adding the entries, click on Save button to apply the changes.
Example: If you want to exclude Skype from real time scan and still wants to scan the Skype folder, you would add
C:\Program Files (x86)\Skype\Skype.exe in the exclusions, so only the skype.exe will be excluded from the real time scanning and not the entire Skype folder.