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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3e5b0e71a30c1458edf4961494d782221a393aaa0e574b8b755bc16fe65e9c5' 
  AND token = 'HOhpubtuF5Ez7vOh9WzmDiA2AQiizc3YvQpmXAgy5oE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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