SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '87d349be7cf753aab6bba043bc5b4b890c5e82427ee07ede862c281e309db9ad' 
  AND token = 'sqt7w2NC3ax6qXRMXWepPSnMHJsHSPIH49VoUx5mSJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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