SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d7581a546e8f249a923fbcf56c8e9e35dff080fa1a3f49581107e3ba38922e' 
  AND token = '+L6cmsCPhjti+T1gAlnm6LhR24ABMZB0KQYPIZu97O0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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