Searching multidimensional arrays

I have been trying to parse results and make sure when I am doing so that I don't repeat the same data. I tried to use a few different options built into php with no luck. I did find an example of a recursive array search taht seems to work but its very intesive and adds a lot of time to the script.

What I'm needing: Does anyone know a better way to handle this without changing the array that I supply to it so something built in like in_array or array_search?

ARRAY EXAMPLE:

array (size=3)
  0 => 
    array (size=3)
      'author' => string 'Jim Beam' (length=8)
      'id' => string '1' (length=1)
      'md5' => string 'f2ebf4d4f333c31ef1491a377edf2cc4' (length=32)
  1 => 
    array (size=3)
      'author' => string 'Jack Daniels' (length=12)
      'id' => string '2' (length=1)
      'md5' => string 'd1839707c130497bfd569c77f97ccac7' (length=32)
  2 => 
    array (size=3)
      'author' => string 'Jose Cuervo' (length=11)
      'id' => string '3' (length=1)
      'md5' => string '64e989b4330cc03dea7fdf6bfe10dda1' (length=32)

CODE EXAMPLE:

function recursive_array_search($needle,$haystack) {
    foreach($haystack as $key=>$value) {
        $current_key=$key;
        if($needle===$value OR (is_array($value) && recursive_array_search($needle,$value) !== false)) {
            return $current_key;
        }
    }
    return false;
}

$agentArray = array(
    array('author'=>'Jim Beam','id'=>'1','md5'=>'f2ebf4d4f333c31ef1491a377edf2cc4'),
    array('author'=>'Jack Daniels','id'=>'2','md5'=>'d1839707c130497bfd569c77f97ccac7'),
    array('author'=>'Jose Cuervo','id'=>'3','md5'=>'64e989b4330cc03dea7fdf6bfe10dda1')
);

$fakeMD5 = '84d7dc19766c446f5e4084e8fce87f82'; //StackOverflow MD5
$realMD5 = 'd1839707c130497bfd569c77f97ccac7'; //Jack Daniels MD5

echo '<b>In_Array:</b> <br/>';

$faketest = in_array($fakeMD5,$agentArray);
$realtest = in_array($realMD5,$agentArray);

var_dump($faketest,$realtest);

echo '<b>Search_Array:</b> <br/>';

$faketest2 = array_search($fakeMD5,$agentArray);
$realtest2 = array_search($realMD5,$agentArray);

var_dump($faketest2,$realtest2);

echo '<b>Custom Recursive Array Seach Function:</b> <br/>';

$faketest3 = recursive_array_search($fakeMD5,$agentArray);
$realtest3 = recursive_array_search($realMD5,$agentArray);

var_dump($faketest3,$realtest3);

RESULTS:

In_Array:
Fake: boolean false
Real: boolean false

Search_Array:
Fake: boolean false
Real: boolean false

Custom Recursive Array Seach Function:
Fake: boolean false
Real: int 1