You want something along the line of
set interface <interface name> unit 0 family inet address 1.1.1.42/30
set interface <interface name> unit 1 family inet address 1.1.1.46/30
set routing-options static route 0.0.0.0/0 next-hop 1.1.1.41
set routing-options static route 0.0.0.0/0 next-hop 1.1.1.45
This probably isn't what you're actually trying to do though - This'll end up with you doing equal cost load balancing between the two static routes, which will end up with asymmetric routing (and your policy thus dropping return traffic). Worse, if you're using NAT, your traffic will appear as if it's coming from two separate places.
If what you're looking to do is only use one route, and fail over to the other in the event of issues, you want something along the lines of
set interface <interface name> unit 0 family inet address 1.1.1.42/30
set interface <interface name> unit 1 family inet address 1.1.1.46/30
set routing-options static route 0.0.0.0/0 next-hop 1.1.1.41
set routing-options static route 0.0.0.0/0 qualified-next-hop preference 25 1.1.1.45