This may work better:

$ perl -le'
my @array = ( "x y.g z 123", "a b.f c 456", "d b.c w 321" );
my @include = ( "b", "q" );

my @keep = map { my $item = $_; my $key = ( split )[ 1 ]; map $key =~ 
+/\Q$_/ ? $item : (), @include } @array;

print for @keep;
'
a b.f c 456
d b.c w 321
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