SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cfb5f2bfc6a56e8b9773bbf5b082f9c7dadb7dab4055832d2bf0cc48f3b569c' 
  AND token = 'h7cEUThkYkoCBXtDeMxZSYRoVbxlzfJGidyogEsOHrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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