SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '451d9920105656614c339f2f5a18a8482711c6c34978b8e4a2b2807a8621ff6f' 
  AND token = 'N/OVVQGSC6ztEreQaAy7Adp1ggYs6OjRSXkiy8LPUfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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