SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a20708262d301fe233555b883374a70ccedfd9460de7d9cd33fb6ae4491054' 
  AND token = 'KiLq/lQ0VL3OGQzGl4PtdfiMI3CkTDA+hHJxRq7mYrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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