SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '725464bd2acbccfed03fef6da4bfdb6dd5cd10e7f37e35a8af6f67715bf59cc5' 
  AND token = 'rM6P+WDmyXQPuNOl48nXAqlzN/eozLP21F4kHu2igxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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