SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39d1614cedf227c00d8ffaf510cad4a84a67c135bc664440ea2e0d1e2ecef573' 
  AND token = 'YEw2TzISVdMliscLzBsfq9qjnln0rG5h/cJUqjRiMSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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