SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f8d488e7583105e566561b719ac234967afc21ce79d34373fa9a7e79c574c08' 
  AND token = 'GZoYuDeGWi7MU5Uqtu3RqxLw0XZM0hisV0Rq9bHRj+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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