Yes, just do:
$query = "SELECT * FROM `config`";
$result = mysql_query($query);
$info = array();
while($row = mysql_fetch_array($result))
{
$info[] = $row;
}
// Get the 1 previous, and after the ID:
$id = '8';
$max = count($info);
$i = 0;
for($i=0; $i<$max; $i++)
{
if($info[$i]['id'] == $id)
$keys = --$i.','.++$i.','.++$i;
}
$keys = explode(",", $keys);
Now, your keys are available in the array: $keys....