SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c197865c981694acf29f270d62ecb50140888545503d133275894f08ade967e6' 
  AND token = '0GtigAGLGENoHeli+QQYejeX/kzd3119fGTvwQYNISI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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