SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fd5cb3efc427750bbaf354c3195e03677ce46390e622b0735be783af42a8889c' 
  AND token = 'Zrd5BuUlZJV/x7MZjFbmu6u46UiMH79hBzePNa1VziE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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