SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2f6a883932e3f59a278c465326fb47ec1a5fd73a064feb929163d738723d70ad' 
  AND token = 'mJBF7EK1+wlYhzZMSs0JHpZCXJyNyyAbjkGFxWDVPDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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