But this way vou have to read the big file often. As supposed above it would be better, to switch the while loops.

untested:

while(<FILE>)
{
    chomp;
    my ($objid,$other) = split(/\s+/,$_);

    while(my ($key,$value)= each (%hash_table))
    {
        if($objid =~ /$key/i)
        {
            print "$key is present in $objid\n";
        }
        else
        {
            next;
        }    
    }
}
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