SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff80ff3394acf7a7a4c1181c21f0890113cfe08bf908a9bc2e14253d414ac2f3' 
  AND token = 'PFZDz6RdsDuiTNDaruHVJQJ79q5ACmOYGm13db7+Y9Y=' 
  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"
    }
  }
}