SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3770b4087ebbe6c4ae2ce76ee93494110912b55c9f547510455fb96d18952078' 
  AND token = '+dDpJQifflhudIjzmZLEJhuQY4VoEvUMrPbpD8aH8RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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