my $against = join ' ', map {qq/"$_"/} @foo;
while (my $PK = <FILE1>) {
    chomp $PK;

    my $sth = $dbh->prepare(qq{
       SELECT value
         FROM value_table
        WHERE primary_key = ?
          # no '+' so it can match against at least one of the words in the list
          AND MATCH (column_text_indexed) AGAINST (? IN BOOLEAN MODE)
    });
    $sth->execute($PK, $against);