SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd5e60e9dec5808597eae5013f4cf6d8f1a771eea0f025a11ae76f4e09b3965b3' 
  AND token = 'LPBnqKzHvZJafTAnVP9D22V1kyvtO7BUMjrPU7RJgSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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