It is possible to get the Lon Lon Ranch Key before entering Minish Village, though this is much slower than the normal route due to a variety of reasons, main one being that Talon doesn't appear until you talk to one of the three Minish in Rem's Shoe Shop after Rem falls asleep.
Reload the Minish Woods area after rescuing Ezlo and shrinking for the first time by doing a save & quit or by entering and exiting the Minish Path to Minish Village. This will remove the Ezlo trigger that is normally blocking your path back to Eastern Hills, allowing you to go to Lon Lon Ranch. Normally, Malon blocks entry into the hole but she only appears after completing Deepwood Shrine, which makes it possible to grab the Key early this way.