SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb0260aa19315db462e88814d451912215a26ca7fe714220cc8cebed48aab3bf' 
  AND token = 'Kq8xalsUA43M0i5zyGAgwm9G6LD+X95ZbqiWO5/vujg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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