SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0ccc5770c932582d4466d9e975b95705e3a256566869caa60465659c08d2d09' 
  AND token = 'ZUeXXgVh0DjUlydjm28U5QK891GRMLW+BOGp6jd5+iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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