SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92c67937a1b186422ec299affab7e65104f88a7e4febe7f1d59a01b60ff1fd96' 
  AND token = 'pNThxyDR3aNJvxjoYPRtg0JaGiPOxTkyr0g/4KBnFVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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