SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e85aac73264ad94e724c80972bddd0385b5921cc131265770282b6026f20266' 
  AND token = '5KXwVIXpCEBmLLcx13vEo0lOBlqTuNTCnaBrAAGA3F4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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