SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcb1ebc661d1da4fe533fba5673de828cd89a2daca29615f55b7ccb0e8ea0127' 
  AND token = 'rHUAQghgoue9JQHK6vkRxGAd5koGD84gCTPSQgAV8jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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