I would warmly encourage you to spread your wings (or booted feet) and pop down to Berne, the capitivating capital.
Direct trains leave ZRH at :13 and :40, arriving about 1:16 later, after a brief stop in Zurich central station. Example: dep 10:13, arr 11:28. The station is an integral part of the airport, max 3 mins walk from customs exit.
Return from Berne at :02 and :32, example: dep 14:32, arr 15:50, which is ample time to pass security and go to your gate for 17:30 (the next train at 15:02/16:20 is also fine).

You would have 3 hours in traffic-light downtown Berne, all of it a Unesco monument, deep in medieval buildings, streets, and parks, and time for a river stroll below Parliament and to the Berne bears. Nowhere is more than 15m walk from the station, or 8m by tram/bus. It is a vibrant and superbly preserved city, rich in the zaniness of the Swiss, as well as its balancing of a federal but largely decentralised state with all the state organs around you, and without the staid bourgeois nature of (for me) a tepid and boring Zurich down town.

On boarding your train in Zurich airport station, on either platform 3 or 4, be sure to be in the area on the platform marked as B or C. Enter to the upper deck of the restaurant car. Avoid the cafe bistro downstairs! Occupy whatever table you want -- most other pax will descend at Zurich central, where you will have a few minutes to get a great table on the 'left' side of the compartment. (which was the 'right' side as you came from the airport, the train changes direction).
Order a splendid (no other type available), freshly-cooked meal, 3 or 4 courses if you want. After 30 mins of valley and river, you will see a castle (Olten) and then be treated to a view over pastures and farms and forests to a horizon of the Alps. People watching is great: government officers, lecturers, captains of industry, students, consultants, monied people heading to/from their private bankers ... and usually no tourists, their being unaware of the delights of a restaurant car.

Walk off your meal in Berne, and on your return journey, take afternoon tea in the restaurant car, or doze in the silence zone car in the first class section.

Trains that always run on time, courteous and informed staff, always a seat, superb food, a picture postcard of a nation that fills your window ...

Enjoy!

BTW: no luggage lockers airside, but plenty in the railway station part of the airport.