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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9eb188c47ebdd13ba20dfea6daa7a4b2466cd7dd167ac7cb8c4af3856386ddd' 
  AND token = '48Y0XKYLln27Dfn52HPlEj5pmovtf9rtgaGgDl0VMbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

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