SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ee4b85e1e02165e288d6917e7610699afd7f793df4e8eef27770683a930deca' 
  AND token = '2K5SkfXJyfJwF26Xm4hNWGq6Vz9OghZs+cw9g2svjBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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