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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5f21ee98dbf7835f8fb5833b3caf8064e4c454f4b7e05f7d0b73f0d92c39bd0' 
  AND token = '4qN7XTkPiy7Hxp7GhKgSlX5LYmB4PsNYvFWz7gbNTdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

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