The O2 Sensor 1 is located on the exhaust manifold before the catalytic
converter. The O2 Sesnor 2, if so equipped, is located after the CAT.
Engines with a V configuration will use Bank 1 and Bank 2 to identify one
side of the motor or the other, you only have Bank 1 so this is a tidbit
that isn't very useful to you now.

Given the relative young age of your car, I'd be inclined to let well enough
alone and wait to see if the code returns. If it does return, I'd look to
the connections being dirty as the first cause, and a worn sensor as the
second cause.

I've read about a firmware problem with some cars (I don't know if Toyota is
included, but I thought I'd throw it out in the General Information
category) that read the O2 Sensor input on a too-short timeslice. The sensor
has a given amount of time to respond, and if it fails during the time frame
given, then it is detected as a failed sensor. Upon tests of the sensors
returned under warranty, it was found that the sensors actually worked
right, but the time frame was too small to get to the set point reliably.
That is, the computer wanted a value in X amount of time, but the sensor
required Y amount of time to be acheived on a reliable basis. They rewrote
the firmware for the computer to increase the response time frame for the
sensor, and this solved the problem. Again, I do not remember if this was a
Toyota thing or not, but it makes for a good question for you to ask.

O2 sensor #1 is located on the exhaust manifold.

The code is a proprietary one for Toyotas, and I assume that the code was
read at a Toyota dealer, and if it was, the condition and actions that the
dealer took are noted for future reference in case it reappears.  The part
should be covered under the basic 36/36 warranty.

The code probably has 2-trip detection logic, which means that the computer
has to detect the problem over 2 trip cycles - cold start, drive X number of
miles, catalyst and O2 sensor warmed up sufficiently, etc.