SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fb63f394725af05606d1fcb4b30e504b62cd0895e709aeda27c101d04a5e6d8' 
  AND token = 'L51QIZau+dQfsI3GFf9g+PbClRqvsP91tg7LhxJ3cM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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