I also tried to find how to open link during searching without touching mouse.
Solution provided by Paul works fine. If you want to make it even faster then install Auto Hotkey https://autohotkey.com/
And here I’ve written short script which opens searched link when you press Shift+Enter.
Version with opening link in new tab
; ==== #Firefox - Essential Firefox shortcut to open searched link / keyword - Open link in new tab ====
SetTitleMatchMode, 2
SetTitleMatchMode, Fast
#IfWinActive ahk_class MozillaWindowClass
Shift & Enter::
Send {ESC}{Ctrl Down}{Enter}{Ctrl Up}
Return
Version with opening link in current tab
; ===== ;#Firefox - Essential Firefox shortcut to open searched link / keyword - Open link in current tab ====
SetTitleMatchMode, 2
SetTitleMatchMode, Fast
#IfWinActive ahk_class MozillaWindowClass
Shift & Enter::
Send {ESC}{Enter}
Return