SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b5737ab47a83f8fe76ec9457a69eeddaa1058d59df24e30317cb3d535114f48' 
  AND token = '3FDJYgA1S6mtxTm/F+qytlLbUBNXxGghg8SCOmcQeOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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