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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79a550f047737df5939670b8a69fe7ef11e9ad0b31323225f78f768f2270eba0' 
  AND token = 'tx1AFdHSnDct3GQE3QRdpWOGatDNsQF1bY90fhjDB1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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