SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '103753e863d744a249986f3eb7852e45150cd7e90f7d608c5dfb3dc71497dd7c' 
  AND token = 'Vjnw9g+aHVzoj/Uz+utUFsGsdKJzRNHZiuaOXSie/Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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