SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbf612227971aa57df430dde318b473999bdd7697abfb72b06415e46faa07bfc' 
  AND token = '+RGRVsDjCDL9GOuKKZKtVaBKk2vKGnHV+0J7o6snB+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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