SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '174b92251330bb6f0e4c73516147bcd1f8259cdd428b1be65e5447e6116baff0' 
  AND token = 'DWB7orqwgDV4Icq5WvLpFGw6dowYiNmTKPIuVPnBi6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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