Sophos offer a free mobile antivirus client for your Android phone. You can get it here
Amongst other things you get
Anti-Virus Protection • Scans apps as you install them • On demand and scheduled scan of previously installed apps and files on external storage (such as SD cards) • Displays Potentially Unwanted Apps (PUA) to help you recognize apps considered unsuitable for business • Uses Sophos threat intelligence from the cloud with up-to-the-minute malware information
Loss and Theft Protection • Can receive commands from predefined phone numbers by text message (SMS) • Supports remote commands for: Wipe, Lock, Alarm (Scream), Locate, Message to finder, Reset passcode • Sends the device location before the battery dies • Informs you if your SIM card is changed
So why not add some protection to your hanset