SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30197a9eb416966fc8bff90f33b4fb196d3fe2a41856a4724f125d78f1fd52a5' 
  AND token = 'ywgAi5r6/K0bjvF9GIUkW+2GZuUi2giTSeQhMbSptKI=' 
  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"
    }
  }
}