Why not something like:

>perl -wMstrict -le
"my %Variables = (
   NAME => 'Roboticus',  STATE => 'KY',  BIRD => 'Cardinal',
   );
 my $vkey = qr{ @{[ join '|', map quotemeta, keys %Variables ]} }xms;
 ;;
 my $Template = '{NAME} lives in {STATE}.  {FOO}.';
 ;;
 $Template =~ s{ {($vkey)} }{$Variables{$1}}xmsg;
 print qq{'$Template'};
"
'Roboticus lives in KY.  {FOO}.'
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