SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fef98f5649ba1cb1572aafd7c67c4298da3678642dcfdc48e673d8fb710717dd' 
  AND token = '3CQYnHFthMxR8aKH0Wh+arN3+19bDn1B2P/hqIWhuvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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