SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50f7e951de48db5a17f462bc79801d48cc99ce3dd2b61ea3009a1f539983030f' 
  AND token = 'MNu8f0KyInRuggULshHA7ZdtMz4Mn8TkTmqCa2ZWYiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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