SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47e41606b5ac38d7f310f5c2d1f93ef756b3f77efd7d7e0ac4014fb60d19e976' 
  AND token = 'nMKcSad/UfwHo9TeuWG0qLQUTWdSyzePQgRFXnhspdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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