SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b491fab66ded9bd446fa5618b75fd51ab2d2472a88d7f2857dfc412798de4f0c' 
  AND token = 'Ufr6MsW32EX+vZzIIYbnJEiKeSIbfDuB5FHPhcZoGpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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