The major ptoblem is that you do $self->{KOLS} = %results;. This is not what you want, you want a hashref in $self->{KOLS} . So replace the line with $self->{KOLS} = %results;.

#access 
my $kolsref = $kol_q->get_all_KOLS;
print $kolsref->{1};

# or if you really want to copy the hash
my %kols = %{  $kol_q->get_all_KOLS() };
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