SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a0f503fcb77d3999251bd0c78ca08f82ee5794a4c29a9be6f08e9b50d4d4ec' 
  AND token = 'mViORyvF9yefDpFGRiMsF5YeC+qEXoA5aOvYY0gPmXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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