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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6798546515de62a63ecdcc08ad34fde93e7aa834e6d2645100316254b336a5ac' 
  AND token = 'io/r/P8l3/mAdq720Y7Itl/q4w3OvZdXsydbS4cK47A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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