SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b34f2e302de1d93e7cbef0c8300a452f52900947dd916db1618bdb87c65dfb8e' 
  AND token = 'rQEE9nqqHI+Y8BWhuqIsfDG7Q/cMMhVzaqLqHu92mgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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