SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '82cc484bf3fe3429377ea5ad39a19f24ca14c34a9607403ccd51baac83811d43' 
  AND token = '0IFHImEU2+Sa9ZZoCG+NLGApkrubOqVyNKJVji+n8DA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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