SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ce9fa8c8a45ca6c4a43d068d2c19ab02efcff01fa46538d850dbd448649b55a' 
  AND token = '343Dudck5kO300FIrmmqLRqhMU6YsBwBf6qScf5AKNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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