In #792, the time complexity became ambiguous, fluctuating between
O(1) and O(n), which is a significant difference. And we agree uncertainty
can potentially bring disaster to the business, the right thing to do is
to persuade users to use EXISTS instead of KEYS in this case, to do the
right thing the right way, rather than accommodating this incorrect usage.
This reverts commit d66a06e8183818c035bb78706f46fd62645db07e.
This reverts #792.
Signed-off-by: Binbin <binloveplay1314@qq.com>
75b824052d