SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83df24f9129c421030aedbfe58a585f16d29262aa785fe0fb941d3ddc2d1fd05' 
  AND token = '4kdbjnmsjfH0khvnrVBxjVLix0izB9TBwhNrLeFXKnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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