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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e4e683e756077eeecb04ba657c368dcac0d068daf8b8d9a9ec05f1c47dae93' 
  AND token = 'MG26jFt6YNu7zUkH9p54HuNxqfqU8iLgiHBDFUPq7yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

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