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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6243483a6e1ad0b0104a089ea66f1124132f7d3e2d8888605c548d1e0bd12804' 
  AND token = 'q6c7X6D/0/zfF2LqyPVde2jDlGDfzOVcW268oECSoHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

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