SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bdf16cac179f35ff924209ae808687d9a98072185cf7a5e250661a81377b9af' 
  AND token = '1nVHgXwW6/QE368Jd2reqT1Y0uXcIa70yo7ZvYJDQo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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