SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aea569fdd6de894f12838765e65c4c21aad0545504a298242968e542627948b4' 
  AND token = 'XovXqcVQ24pHmfiSyDSyuUxjLpww84iiU+cb7IFyVRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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