SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b28fafacf1c52cba26cba6b96462a293124e7f048827d092d298aeb383239151' 
  AND token = '8bebfqE5Hv+//JiUHdQFpz6vdjY+D0raCmaoggaZ9T8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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