Hello Ian
It looks like a standard DNS query on port 53 - the colon 53 part - either being made/returned from/to a computer with an IP address of 192.168.1.64 (presumably yours?) to what I'm going to assume is your gateway/router 192.168.1.254? The port initiating or receiving the request is one of many ephemeral ports Apple (and others) uses to establish and/or maintain transient requests - 56497.
This is my reading of it - perhaps others can offer more insight? I personally think its nothing to worry about. If you want to know which application and/or process started the ball rolling you could use a number of command line utilities:
sudo lsof -i | grep LISTEN
The above should show all ports that are listening. This one:
sudo lsof -i -P | grep portnumber
Should target all active connections based on the port number
If the command line is not to your taste installing and monitoring something like 'Little Snitch' should show you something? Probably mDNSResponder (Bonjour etc) as it uses a number of ports in the 50000+ range.
Apple have a support article listing what ports they often use:
http://support.apple.com/kb/ts1629
HTH?
Tony