Polybar

[module/yubikey]
type = custom/script

exec = ncat --unixsock $XDG_RUNTIME_DIR/yubikey-touch-detector.socket | while read -n5 message; do [[ $message = *1 ]] && echo " <key-icon> " || echo ""; done
tail = true

format-foreground = #ffffff
format-background = #ff0000

For this to work, you need a correct ncat binary (nmap package on Arch).

Alternatively, try using nc -U command (and installing openbsd-netcat package on Arch).