SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9a81a59164bac0f888689e900a7ea95d828d56d8516d396e137068e354afbe67' 
  AND token = 'OvZeKfsH8et3tzj14qygH6tzYsIewuwfvQskVFeTAKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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