SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '24c401eb5ead5d31479902ef056800db9b717d4ecb42ff6446d4a0620ffd53fe' 
  AND token = 'A4Hm0fdBFyYzQimkjbCW2O1JPngo6NUMgJPhr0xhok4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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