SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdd17f3831693a51cea72cd2bba85f8f59a1e651c4aa78911044640ca6df2779' 
  AND token = 'e4NUuBCm/ZIEpug6kZOXmKXi7hVYdm2Pjt8zD/++Vms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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