SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '025b1f5c4240a821d1fd32fcf9ed9bc38b2f797271546bd97214376148dbcd15' 
  AND token = 'kI2hBvETEThqXAsbUukudrPNz0JWf3DQnQWQZ+tSYzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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