SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f3aaecd3068cbd7c1af1d94e991680d7ef0a18a049f670e9942da19f8d318f9' 
  AND token = '/PnAJwNYUY1S7I6MSaP/Pgq+5Zx5DLK48SZ2iSim80g=' 
  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