SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce440535421146ceae5c885f541fd2160d60ed5054970dd9d8da0293769bfcec' 
  AND token = 'isljcHGqIQUHXYMaVQP/abJFnPExI9A7APF4eGaq8oM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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