SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14fb28a803518bdaaa28a064e7060373445f6ebae1f537506d1b93738279aa9f' 
  AND token = 'xosMflR4UMJxZc41DgIsio3ueXAceovOFW1nI2UbdN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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