SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9badfacc857be5a34f518f06c086f2608399fb7b8eded2c0d3887a346865a89' 
  AND token = 'XfLtgJRgkBOswejvf2h5AWn3plfO8vldk75FikttQSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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