SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '32ae566115bd7546ca3588052eaa0d984a71645b055135f2dde160fcd1e334c5' 
  AND token = '8D1o0eexhmddaLDBTIH428qi2eW1BVzR6+9amTYJxZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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