SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3fc9e471b693d35932c796f4fd65a796346d9168044738aa3733c35b5a4da82' 
  AND token = 'O+Po12gxY6KeVTRWqVLZrbF4XAqcHMZu+ta0/M71Xrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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