SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '217202393aebe35220d87354a08d619f17a5d6d85ea75f5dbec860dff5f173de' 
  AND token = 'pbNRXg2DadrC0arRnpwZ+zrD2NOIpFrl/oVCplZxleo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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