SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8fc66c296c45be0af006b124eb8ccadc0df246f6a3c475dc3ecd06c65444af' 
  AND token = 'QmpCYmV8IFUwtMEyN+Opagq+NGCle0+t/uneu1iG8nQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}