I dont think your fish will care if the pump is on. If they are hungry, they will eat no matter what.
My fish will eat right in the air stone bubbles or right around the splashing fountain or waterfall.
That being said....
There are many electronic plug-in minute/hour/day/daily programmable timers out there. They are quite common and inexpensive.
Even the very simple mechanical (non-electronic) cheaper ones people use for their table lamps have an override switch that resets when the pin is touched again by the moving clock face. So, your person feeding can just switch it off and it will reset on it's own once the "on" pin makes contact. They come with several removeable pins. Some to trip it on and some to trip it off.
Some timers have the pins built in. You lift or press them in for your desired action.
This is the type of timer you will probably want. Simple as can be and quite inexpensive. I have a bunch of these around my house.
Get them at your favorite box store, hardware store or online.
The only thing you'll want to make sure of is that the wattage of your pump/filter doesn't exceed the maximum wattage of the timer. I doubt this, but thought I'd mention it anyway.