SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394cc3d80d3b5284e72ef28c753c4111c8dfd98733f087579f8072dad39c9fdc' 
  AND token = 'XQQndAW+SbWFn747eZ0J5pkzDxdNr31XCOXRovT/KqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00213

JSON explain

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