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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49785e3a2984a481c013f099d1f90b9225dadfd6d7e3a3094d3ae819f7c97744' 
  AND token = 'PaSBi65Inp967SSAhe5PfoneCBX6WlrRQ25vBDgXWQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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