SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56ff9346b155c28b1d8dc6daae70386081a5eed1272b932b1169ae0e5ccbacae' 
  AND token = 'fU4WubhIbueIOuEWELWFR82YRoe9zaqY0AQWPcloQkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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