SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fdab6b931175ab8fb4a2dff2a96493ff7da1c71986fd3b43135faed4677eb24' 
  AND token = 'umIYsnhoWO0LZAnVYDIjUzN7GcApls2Ilk8Xc0vg3hY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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