SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ccc6eb00744cd0c9ed85f4746dff6a865691739efa27974c1f8220697cbc271' 
  AND token = 'XZaIypaSVmzg3wcpFrgwVm4iMbRsXlnc1S95PkdkBqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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