SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '928ff585917b485530551d7a44b67c204415e4d6dfe0b0bbf965dd3256095f11' 
  AND token = 'Snq//PtN1RffK+X1N8lN82kwo6MxfXrQa4MPPr6LAVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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