SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1cfecd3a718f46166ff23f4f4db4ac7ccbda831da84bcac85734ffa1679ed7f8' 
  AND token = 'CHPedf3649iKOjWpGN+nHWlOVxQZ0Jj7mguTBYBj+CA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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