How to power on/off Adafruit FONA 808 with KEY pin from Arduino?

Hello all,

I am trying to develop a project with Fona 808 (this model Pinouts | Adafruit FONA 808 Cellular + GPS Breakout | Adafruit Learning System) and one arduino Nano. I connected Fona to Nano and I can send SMS is working well.
I would like to power on/off the GSM shield with the Fona KEY pin which turns the shield on/off if it is connected with GND for 2sec in order to save energy.
For the moment I do it manually (when I connect the Fona KEY pin with Nano GND for 2s the shield becomes on or off) and is working perfectly, but I want to do this automated from Nano.

I have read in adafruit's manuals:
"Key - This is also a super important pin (but not as important as Vio). This is the power on/off indicator. Its also tied to the button in the top left. Tie this pin to ground for 2 seconds to turn the module on or off. It's not a level signal so it isn't like "low is off, high is on" - instead you must pulse it for 2 seconds to turn off/on. The module comes by default off. Tie this permanently to ground if you never want your micro to turn off the FONA for power saving".

How to pulse it for 2s from Nano? (see in red).

How can I power on/off Adafruit FONA 808 with KEY pin from Nano? Can this be done with a Nano pin or I need a relay or mosfet? .
Does anyone know how this can be done?

Thank you in advance!

Nobody knows how to power on/off Adafruit FONA 808 with KEY pin from Arduino?