SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e9ddf5b798b6892334b5b6439a6e080fe6f5ebcbd51889433dfa6463df4f930' 
  AND token = 'IWd+ypvdCVqGni/bvLcEWk+xhrMJxbIzm578+IgbOt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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