Build an array of the keys ordered (descending) by the epoch; pop and delete until there are just 10 left; and use the remaining to output in order:

#! perl -slw
use strict;
use Data::Dump qw[ pp ];

my $now = time;

my %hash = map{;
    "url$_" => {
        title => "title $_",
        EPOCH => $now - 50 + int( rand 100 ),
        DESC  => "Desc $_ ",
    }
} 1 .. 12;

pp \%hash;

my @epochOrderKeys = sort {
    $hash{ $b }{ EPOCH } <=> $hash{ $a }{ EPOCH }
} keys %hash;

delete $hash{ pop  @epochOrderKeys } while @epochOrderKeys > 10;

print "$_ : ", pp $hash{ $_ } for  @epochOrderKeys;

__END__
c:\test>809852
{
  url1  => { DESC => "Desc 1 ", EPOCH => 1259396887, title => "title 1
+" },
  url10 => { DESC => "Desc 10 ", EPOCH => 1259396825, title => "title 
+10" },
  url11 => { DESC => "Desc 11 ", EPOCH => 1259396896, title => "title 
+11" },
  url12 => { DESC => "Desc 12 ", EPOCH => 1259396905, title => "title 
+12" },
  url2  => { DESC => "Desc 2 ", EPOCH => 1259396822, title => "title 2
+" },
  url3  => { DESC => "Desc 3 ", EPOCH => 1259396833, title => "title 3
+" },
  url4  => { DESC => "Desc 4 ", EPOCH => 1259396873, title => "title 4
+" },
  url5  => { DESC => "Desc 5 ", EPOCH => 1259396824, title => "title 5
+" },
  url6  => { DESC => "Desc 6 ", EPOCH => 1259396833, title => "title 6
+" },
  url7  => { DESC => "Desc 7 ", EPOCH => 1259396827, title => "title 7
+" },
  url8  => { DESC => "Desc 8 ", EPOCH => 1259396910, title => "title 8
+" },
  url9  => { DESC => "Desc 9 ", EPOCH => 1259396843, title => "title 9
+" },
}

url8 : { DESC => "Desc 8 ", EPOCH => 1259396910, title => "title 8" }
url12 : { DESC => "Desc 12 ", EPOCH => 1259396905, title => "title 12"
+ }
url11 : { DESC => "Desc 11 ", EPOCH => 1259396896, title => "title 11"
+ }
url1 : { DESC => "Desc 1 ", EPOCH => 1259396887, title => "title 1" }
url4 : { DESC => "Desc 4 ", EPOCH => 1259396873, title => "title 4" }
url9 : { DESC => "Desc 9 ", EPOCH => 1259396843, title => "title 9" }
url3 : { DESC => "Desc 3 ", EPOCH => 1259396833, title => "title 3" }
url6 : { DESC => "Desc 6 ", EPOCH => 1259396833, title => "title 6" }
url7 : { DESC => "Desc 7 ", EPOCH => 1259396827, title => "title 7" }
url10 : { DESC => "Desc 10 ", EPOCH => 1259396825, title => "title 10"
+ }
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