SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8dd73873baa4b90d0d609977089735140c602c864f3e5a99cbc03f843bdaf5b7' 
  AND token = 'jQh3WV05I97tdTqU3M8ZNRN3JsIsxFrThycEGJNnr5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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