If you're going to clean the MAF, you might as well replace the air filter; at almost a year and 25k due for replacement anyway.
The urgency of this is up to you of course, but I wasn't in a huge hurry to get mine taken care of. I reasoned that if the engine was running smoothly and fuel mileage didn't change, that was a pretty good indication that the engine management system was continuing to meter fuel properly despite the condition.
If it's just an intake leak, the engine is going to trim the fuel metering according to the O2 sensors, so the mixture will wind up right in the end; it's just that the engine's MAF data doesn't match the O2 data and that makes the code.
Like you said, it's unlikely that both O2 sensors would fail simultaneously, so I think these codes generally indicate an intake leak. It's easy and cheap to pull the MAF out and clean it though, so that's a good place to start.