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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c666622f190d2d29c533885400df276ea1aa3a8e8be481f52f6ac87433a0c8a3' 
  AND token = 'PttKmx9kD2luKmnSHNAzZJUo3NAdudWdbFy7Ocz1iAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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