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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a78979690e402d6e6b7722fc60a42dc9a9369c8bb66837746a76030ed9ed63d' 
  AND token = 'pLNwgRjESECvTr9f8xzWwxm7F1gx0HZBcaoFJA8iYhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

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