SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51093f80115d5b4000f59f8e9c516e9d5c4e8c5785ee55e5f98278412eeb25fe' 
  AND token = 'imD5txLQyVgbtYeA9DcNuIlwk9OVEqr/MguGUurKmTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}