SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7ad635af04f62f71f903badb999b354a9cd70fe31768ade14a5c098c8ff12a5' 
  AND token = 'HcWUWN4wivrTG53l5DB29GVe1/LMxQUnWle5EbtfQFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}