SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '728fc3e3013ec4b995f648e1fb0eb24e9058178d8e9353e9a7b6a75e1c8653cc' 
  AND token = 'rf4ed13gO6rBVs04Sc5A7HSDNYmQtv+o2jOSJTlYN8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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