SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328abbdda5a192eee0f42e64da5793893618123741c5166f971920c6e79429fe' 
  AND token = 'mtaJhwYs+GnGdhli7l5qNwQMC/NX8g13KNK7XnPgo+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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