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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '859e728e4146e4cb1988b9d7fee2e2fa79293ac6135ab0e5a46dca93b8fa2195' 
  AND token = 'ZNznwMCUDLGEad8fXj6sF2ZgI3xSyZOcWqhVpbNwZlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

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