SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '299048ef25a94150148f60147c439afe54dc088da7064dc5bb78486324242eea' 
  AND token = 'YViH5OEGa2VHh4UWqffkhZCLq1jy+q/wR2xXlaCsLds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}