Your "records" clearly include 3 lines, so just read the file 3 lines at a time:

#!/usr/bin/perl -lw
use strict;

my @lines;
my $count=0;
while( @lines[0..2]=( <DATA>, <DATA>, <DATA>))
  { $count++ if( ($lines[2]=~ m{^--$}) and ( index($lines[0], 'ABC SET
+') != -1)); }

print "count: $count";


__DATA__
1-23-abc45 (11:01)    ABC SET foo foo foo.
Foo data foo.
--
1-23-cba45 (12:02)     ABC RUN foo foo foo.
Foo data foo.
--
2-34-xyz21 (12:03)     ABC SET foo foo foo.
Foo data foo.
!
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