SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54853db4c17f096c688b2dc72f14f2efe3e8cc3fcdb9b393f82bcbf3a7554e5d' 
  AND token = '5IyzEIGHErW+CGeCOSYTS3YzCTX+vPSnL7hH0DkHQT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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