use JSON;
use Data::Dump qw/dump/; # Debugging only

my $raw = <>; # Raw JSON text from your post
my $decoded = decode_json $raw;

say $decoded->[0]->{dns_zone}->{records}
     ->{SOA}->[0]->{dns_record}->{expire};

# dump $decoded; # Whole mess

##</code><code>##

2419200