SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd8c7cbfb4e2fe14402b78c02ed57b2d06c815cd87c4b029c0e64fa4c93656fd0' 
  AND token = '5E6Q3CL1yT0i13TZ8BOwn2ifyxeyq6rBahS0ekxMcjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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