SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6bbff55db56d9b2badd9fa5d82cff71f1cc3352cdbe283638b9eb71687088b7c' 
  AND token = 'q/PO39qyb6JQpj5ziWQxtUvMO29zmzwICiBm43oXjqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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