SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '711122843d5046c497ec2b0398d1d8d30146aec58ef1a845d3d0ef0284bc7e2d' 
  AND token = 'PxLLvYK4duZMDyPG0j4nYiUr4aEbimMyDtNtQJWpCro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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