SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ddbfa1136fd71473bb3c600277b61323dfd0ed807e8d5360bda7ee19ea06cfe' 
  AND token = 'CgTjJeJfmfyiU1AXVd24QWrcxVsTkEAuNZ4XtPhA3Pg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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