SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a65d91a2f1cbfc6f6d132693dd84abddcb9582787396c8bb456620e7ca7df826' 
  AND token = 'iIE8t3sgJk2MGB9YwhRXRcVSWDSaCvg67iZiSomUCwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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