SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf076b39ee180691a60d3ca246a3cb60555b0d454c94fb16946d1e4d658629b4' 
  AND token = 'ZkuX1TjgFZe9DWy+iabf1YvT/PYY3ISTquc2RiOClQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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