use POSIX::strptime;
my $timestamp = "2010-07-23 19:44:43.523";
#remove milliseconds
$timestamp =~ s/\.\d+$//;

my ($t_sec, $t_min, $t_hour, $t_mday, $t_mon, $t_year, $t_wday, $t_yday) = POSIX::strptime($timestamp, "%Y-%m-%d %H:%M:%S");

my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
   localtime(time);

if($t_year == $year && $t_mon == $mon && $t_mday == $mday &&
   $t_hour == $hour && abs($t_min-$min) <= 1){
#dates match
}