SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8df4d7f91f07fd61d68fdcc215fa682245c08a24bff70f8005af57fce800df7' 
  AND token = 'U3ObJFmZKY2m5GbqDVg64rMc6KI+G+BmSCc+lZNXjZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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