SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c69a1dcef5639f214198815a6e4014496b4e69385b154333048c81373445bad' 
  AND token = 'ZOYiRM7aE/WpZjyRYUMFVXFUoT2QdH27/CPOIZWH31k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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