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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc9740ffc34b038b76f26c506185e10c0b87d7001a07de06207c5894a0f0dac3' 
  AND token = 'TfZls49InyY7WqLdZ8jFBsln56BSAMBxSwJZrkAPMlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE								Impossible WHERE noticed after reading const tables