SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '01a0d646e2b08c1bb8715d754f83dbd8c03b34c0517f60a938afe575ce9064b8' 
  AND token = 'xhm+d2MFpYcwLR55N7eyQRY9ni933g0XcoadUit9GSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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