SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9457469943be2d8fd80b04c8cf30fabca4a92f401f38fdabdfeec2d88255281f' 
  AND token = 'pRlJqk7vc6QQbk2bXZbBhiU3J4i6i0ZbEvA7D4GEkQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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