SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f994ccecdbd0f1ff66a1ab49d108d59e9a1cb75264eb8f211f738f377039989a' 
  AND token = 'IKpURjDAGqnJrKP5qQkunnCeGWrumLE72FbpCzgsc8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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