SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a3bb87f298ed4cab92162c78506ed3de85e74703a1ef1c9b379402bb2cc3b6af' 
  AND token = '20ZS29QDjZBUikXDy72F54yTQR8NdYn/EaIfnPxerl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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