SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aab4d1db0e3579a937bfed690f406746c8686f8b0b4678db9593ec8f5163775' 
  AND token = 'oGotzcPQQHuRExFXcXPcQS2o8j7DBayV+BO2uYxBb4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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