SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6500ed30a835258aeecab15a51c07b062e94c10f32adf4c5ce31a7bb0dc56333' 
  AND token = 'QXEuhpCw/IAPqRo/FC6+OfLwjiFs7oFEwrleyTfYbc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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