SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7d8fd77f617165b020f40dd611964f25180d8085817ba68d4349642a79df7aba' 
  AND token = 'yg9WWLCbrZEQPAB1tzKQ83lC1NTtsWP5cNznuJchOgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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