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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a98efd7281df86a9cf6c9d2e8b489c51ee30ee7b507fe600a258e4b43381046e' 
  AND token = 'qplDQiYQu7Nb5wGZb8V7NMNPLpCKF7dEgaiNq3jiAWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

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