Here is one way - the hash I use is not a dbm hash, but it is trivial to port it:

my %h = (
    8   => 'value',
    3   => 'value',
    102 => 'value',
    4   => 'value',
    1   => 'value',
    57  => 'value',
);

my @keys = sort { $a <=> $b } keys %h;

my $try = shift || 5;    # this example allows user to specify on comm
+and line
my $low = 'not found';

foreach (@keys) {
    $low = $_ if $_ < $try;
    last if $_ >= $try;
}

print "$low\n";
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Jeff

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