You can't tell if a code ref actually has code behind it that way. \&anyNameHere will return an apparently valid code ref. The only way is to actually invoke it, so do the invocation within an eval block:

print $_, ':', eval{ $_->(); 1 } ? "S'ok" : "Uht erd!" 
    for sub{ print 'good code' }, \&doesNotExist;;

good code
CODE(0x194a9b4) : S'ok
CODE(0x194a954) : Uht erd!
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