SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '56ca87401d55c5de99a6507e26f4615ac1c21b3a540b19dfb737a6e33b7aea2f' 
  AND token = 'MgzyHcYonUXOsh4sPOSVi0TJdHh/Dfn0ZnH8MhXulK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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