SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7430a627a058f80b74cbd0e8ebd8575f2e5bf37f5b07b83c9768bdf268cb6635' 
  AND token = 'r1SZicyzJAxpHlROOvfbOzAvWRYIS9sEQsdkh/0oNxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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