SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2152d4ba4fde35ae5fcf6414ee434bd4594bfa3531fcfce11e84b5f671751b21' 
  AND token = 'mjFth/lg1ZrdrBEN47lYoakbTY7gK+IR0hzz4g3Fprs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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