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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73fcfe74bfb2bbcd51a660dc3d33568c6f2b0ec68a077033aa49539782f9af39' 
  AND token = '8yfNhskGI7IrQsnPT4uYTY0dISOSyNb4DdiZ4MN7M6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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