In Adventure Comics #242 (Sept 1957), Superboy meets another lad from Krypton, Zar-Al the Krypton Kid. His father also believed Krypton would be destroyed so he sent his son in a Time Ship to Earth to find Zeelium, an element that would stabilize Krypton’s core. The Krypton Kid meets up with Superboy, but they find no Zeelium on Earth (it’s not clear why they didn’t proceed to scour the universe for Zeelium).
After Superboy convinces the Krypton Kid to stay on Earth despite not finding any Zeelium, they have a couple nice adventures together. Ultimately the two super-lads try to sacrifice their own future for the other and the Krypton Kid wins out, traveling back in time and space to Krypton to perish with his father.