Dude, a FROZEN KEY? You know, in 3 playthroughs since 1.3, I've not gotten one single biome key despite farming an Ankh Shield in each playthrough?
That's right, I've managed to farm up ALL of the Ankh Shield items except for the Nazar (which I always do Pre-Hardmode) and in a couple playthroughs, the Bezoar, without getting a single Biome Key. In fact, my first 1.3 playthrough, I killed 150 turtles without finding a single shell, plus all of the bees, slimes, man eaters, etc (and two uzis in that one playthrough), but still no Jungle Key.
I still do not have the biome key achievement to this day (nor do I have the rainbow gun achievement by extension), despite me primarily using the Hallow Desert to farm for Fast Clocks, Megaphones, and Trifold Maps.
In fact, I have 5 Blessed Apples across these playthroughs, and 0 Hallow Keys.