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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81769adddc5977f47197115d733e7e2dbb676279a4e8b7f4c781767af99c9c1b' 
  AND token = '4N7Ss0xVQnGaA50yk1hylAHEnCg06fcmpYjcdJls3v4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

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