SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34891f822ec844ff27ba33fc3b3da7caf93d6fcb496262fa9f73693e56a32f03' 
  AND token = 'BjNG5plGYY1lB0skZYJKq/uZrkH9oERUN/0ZfJTuBFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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