SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67343975ef8df55c83d9fdf62bdf628e2b51b738bebcb3713492ab389868b0d1' 
  AND token = 'GZ5b9rMUz07hFBkQWK9gSqFJRFXTOROOIPsUITjgZJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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