SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4840684aa4506c2c192e3323918415f242139d906f1b255596e8479694dc85a' 
  AND token = 'nolhjLdw49z+/BVQBqrkjYSktO/zhvMwjcJhQgQl/fs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

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