SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '380b753cdcaa7b67e6673c6cc8e8d362e59958b0dc6afa3a9cd5e2a438d2f973' 
  AND token = '5w+B/OlgVe1wf4a0trRRyu+Crt1FBzK1dp+qJfJlI7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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