SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675f7521c58d5e19788b24be0fe23e5e09f1d48e286917408006c833dd8c5d28' 
  AND token = 'OFlUHK0xbXIKhblqRNxdEiG5zDg8WYdivbHpTIhwB+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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