SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aa323d9e07b4c611e62c872e6334d78297dc35991952aaaf4876486be4af56f' 
  AND token = 'pOZJTqd3IE/yi2Ygoz1CD8dsAGe5Kh+pBNz2bYZOk5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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