SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddbb7ff2269d6d82af890acd1042b9cae36bfa123c0d5b614caf68db0bcc6899' 
  AND token = 'zzoKvJqKYYl2G1PvtqDTBUUVd60sbhh/ariVNcSo8Wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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