SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18b9b8adb5bb6a8b35a75ac10842f0f6337ec99ecd11ee8dc9665bd8102cfd9d' 
  AND token = 'w8RIJnWDFIYx2rvuKF6YW5tM7BvkeGt6nxasokIbBTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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