SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '905be2bf1853afa877edb9896c85cf2928c621e1552609d7cfc036fcd4fb25f8' 
  AND token = 'D/dpza+BAI3jDPVLbkPKW4a3dkRFnGdTjkYjsP4v9Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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