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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a3fe6be9e01d72308b35ad5b7f1b3a39bca5fb7bb7a3294673b9b73faab273b' 
  AND token = 'IIvqhmZQKGSEgjb95WdSZXmDtSb9xPuXlkSioK2xPYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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