SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7702f43159e97214aecdba5552d1893fde9878b20880b69348164bbac4f09ad' 
  AND token = 'jlx+du/6pOSCJEfp9uwO3W9wWBNyk5KBWdF10NqScrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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