Are you worried that someone may break your AES/Rijndael 256-encrypted database? If your key sucks, then yeah, you should be worried.
It's always good to elaborate what your fears are.
If you're afraid that a government agency may have the resources to compromise your KeePass database - I wouldn't be worried about that, they have other ways to get what they need.
If you think a hacking group is looking to break your precious database of cloudy accounts, then it's more likely that you become a victim of a drive-by (e.g. malware on your droid).
In all cases, the baddies will go after the lowest hanging fruit, and in this case it's not the KeePass database - it's as solid as you need it to be. However, your Android may not be as solid as you think. The endpoint is usually the weakest link, especially if it's a phone.