SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f4419c6a75bf26ababba37e65c4c0d83280a43aa337e75c3105b5bbf3d363e3' 
  AND token = 'Slh9GHBTfLYPBTD7l5kRzYWg3u2TTrjftyXySvcJupg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}