That's a pretty good reimplementation of looks_like_number, but it doesn't answer the OP's question. He still gets the same answer he currently gets.

sub _isNumeric {
        my ($value) = @_; 

        no warnings;

        return 1 if ($value + 0) eq $value;
        return 0;
}

my $var = {
            'key1' => '1',
            'key2' => 1
          };
print "Key1: It is a number\n" if _isNumeric( $var->{'key1'} ) ;
print "Key2: It is a number\n" if _isNumeric( $var->{'key2'} ) ;
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Key1: It is a number
Key2: It is a number
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