Is there a scriptural basis (preferably in Doctrine & Covenants) for the priesthood being restricted to men (at least on this earth)?
If not, what is the explanation for this practice?
Not explicitly, that being said, there are a variety of scriptures that indicate that men are to be ordained to the priesthood, rather than women.
There are no scriptures where it speaks of the priesthood in terms of daughters or mothers. The Priesthood has always been a Patriarchal order, even in the beginning with Adam.
“These are the names of the sons of Aaron, the priests which were anointed, whom he consecrated to minister in the priest’s office.”
“And thou shalt appoint Aaron and his sons, and they shall wait on their priest’s office…”
“The duty of the elders, priests, teachers, deacons, and members of the church of Christ—An apostle is an elder, and it is his calling to baptize;”
“And he may also ordain other priests, teachers, and deacons.
“And he is to take the lead of meetings when there is no elder present;”
It also must be noted that all interactions related to the priesthood were males. Christ himself, Adam Melchizedek, Abraham, Noah, Elijah, Elisha, Moses, Aaron, Peter, James, and John, John the Baptist… All told, not a single reference to women when the priesthood was explicitly given or received.