SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6d688d7e51aea05b05563aabae6645fa0832bbb84e936b27e4ff1234d6d01e8' 
  AND token = 'dQoQbE6RRyDAJh9LIrQb74waqI6qBFKH14qPvf++oQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}