SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b8863784f255a1b3977b2ac61957fa1a589899e806a76eaaa46c90d5cd6a195' 
  AND token = 'HX8lziQOPH8ApuiGpzLtEmHRUC8kVBYPYyxZKGChYX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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