SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8411ed7eeb6224bc143e5a187e828d607320126eec003ade90f268cab33d560' 
  AND token = 'fH2jPWdAjcb/HZDguDGOLgWVHXSpQUe1j/Rh+BVM6Ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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