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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83e636ca2263af8a505801c14874f5d00e88b65009bfed9f30ee21fb77157580' 
  AND token = 'QQvH4ddi5QzfCThsW5C88vAsXwx8v8uza3qdgsmrano=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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