SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '06dec09510a41275e3b49ed61709be88c35151c26c8b2a31e31fa9344894f9a4' 
  AND token = 'KNB5wgSWkYvd0mxykx2z0ZhQ5Cjo4pUiyq8T8MKtGFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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