SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ac6af83c84d68c7cc18caa38146392b545e5b220b1893105c260b07daa5aa4' 
  AND token = 'LpMU7Wlf4iXKjNU6adQkzkvbZvhCys9ErQahLfNKsOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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