SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '606b9bf1a5fcabe8e08c5801c23ba16296a127eeaf01ab6da7a8f77a7374c446' 
  AND token = 'NUSYW1oHkKAEH7gIe9/DrrCk21cOqCZVnXOiOifYhCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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