SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b355011aa4e8f3c5584e5dddedad1c19edae783c26d73811f75ebea6f20b1cb8' 
  AND token = 'IlLb0bDoaiuDDHNNJIIJquvaYyDB7fj7oC6BNqDgCkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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