SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aafbf998e0884b5ac3dc34f4dcc9882a788732313f6e8f4589c2e505ce87991e' 
  AND token = 'cREZvBWQXxSNo21vQUkBt+zttwrFC/w544b8DS8/T1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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