SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08cbce810dea083605a7e820388697d4330767174bd7918f983ebf64995efd2f' 
  AND token = 'ShJZ+N9WaUVIH6jTgBNBCHwwZ1zOdTteCRrYsfqKxNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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