SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a0675c4fa39e997a3c84d543b286bcb4da24839fa073542e7cbd8c1bd31103f' 
  AND token = 'y3M1RyX3ipRS38bRlOMXLpXShYdMysJcCOt/uyVon8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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