SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a683917bd7046980df55ea41dae25f84c9de633b1d780fe7f0efb18138041ce' 
  AND token = 'rGlZ2nntlMD0IHae83FxOSdcsgiVjtjX46BuiVqh/hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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