SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2f37209aa9be4be172f15ff6cb0fc658fc59fb8efd3cdb86fd8040c1a13b6cb' 
  AND token = '61MxSTMTGjIaXmwygXB4/MDNDAPdCUY5KkD4KSUwMDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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