SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fd0fc31135ff731a800d1eeac93f321ab17eb1c99e6b7b38de4648efcbb6a31' 
  AND token = 'cEZ9Qm6maCD9Dx99fX3q9P42a9AwY3fdfmzE20903Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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