SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97615b3f95a80c8d10f6ed114a94823ffc3058cd72dfb3ff7f641f1285abb4f8' 
  AND token = '75wq1IwjKcDL1T/egGkUM5rKQ5IV7sN9CPzWYIbJwBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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