You keep creating a fresh session each time you run that code. You need to create it once, and retrieve the same-session, using the session id. See Apache::Session

use Apache::Session::MySQL;

my %session;

#make a fresh session for a first-time visitor
tie %session, 'Apache::Session::MySQL';

#stick some stuff in it
$session{visa_number} = "1234 5678 9876 5432";

#get the session id for later use
my $id = $session{_session_id};

#...time passes...

#get the session data back out again during some other request
my %session;
tie %session, 'Apache::Session::MySQL', $id;

validate($session{visa_number});

#delete a session from the object store permanently
tied(%session)->delete;
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